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Doncaster BBS 2012 Early Analysis

19th November 2012

I’ve just started to work on the information that was gathered in the Doncaster Bird Census for 2012, in which many volunteers helped to assess the breeding populations for a selection of open countryside species. I thought it might be interesting to provide some feedback for readers of the website, and invite comments and critique, so we can build a meaningful picture of the breeding populations and distribution of key species around Doncaster, and look at the longer term trends. Results from some of the ‘study areas’ are still awaited, but we managed to cover around 50% of the DDOS district land area, so it was a terrific effort from all concerned in what was a dismal spring weather wise. Eventually I will write the findings up a little more ‘scientifically’ but for the time being here are the preliminary findings – one species at a time each week or so through the winter.

PART 1

No better place to start than the DDOS emblem bird,

LAPWING 

About 270 pairs were counted in the 2012 census. Extrapolating this for suitable habitat in the rest of the district, produces an estimated DDOS area population of around 400-450 pairs.

The last census in 1994, using the same techniques (and many of the same volunteers!), suggested a district population of around 600-650 pairs.

So sadly and in line with national trends, our Doncaster breeding Lapwing population is in decline. Hopefully readers can suggest the many factors involved. For example high acreage of ‘mustard oil seed rape’ as I call it, means fields already above knee deep in vegetation by April. An almost constant turn over of soils on the organic farms means birds get little chance to settle undisturbed. But these are just suggestions and it may be more complex. In the eventual detailed write up, I will focus in on certain individual study areas to compare trends from 1994 to the present day.

So, more soon on the rest of the waders, and then the raptors and species like Turtle Dove. I hope readers find it interesting and engage with the series.

Best wishes, Nick Whitehouse

 

5th December 2012
Part 2
Oystercatcher
Breeding was first recorded in the DDOS area in 1979, with a pair in the Idle Valley. By the time of the last full survey in 1994, there were 5-6 pairs noted in the district.
So, how did the species fare in 2012 in the Doncaster district?
A total of 29 pairs were counted by volunteers in 2012. With some parts of the district still to report, and some parts not covered at all in the census, I would estimate that the breeding population is in the region of some 30-35 pairs. This represents an amazing increase on the baseline measure over nearly two decades, the increase being matched by a substantial increase in breeding range also. 
More in the eventual write up of the census, but comments are welcome from DoncasterBirding website readers on the possible factors involved and on trends elsewhere.
Nick

11th December 2012

Part 3

Here are a couple more wader species for the website series, giving the interim results of the 2012 Doncaster Bird Census.
Ringed Plover
Whilst there are still a few study areas yet to report, the census in summer 2012 has so far yielded a total of just 6 pairs holding territory in the Doncaster district. This compares to the 7 pairs noted in the 1994 survey. It is always difficult to draw too many conclusions from the results of any particular breeding season due to year on year variations, but the results do tend to suggest that the overall district population is relatively stable. Ringed Plover first bred around Doncaster in 1978 and the population had grown to at least 10 pairs by 1984. It seems that further population and range expansion has perhaps been halted by limited suitable habitat.
Little Ringed Plover
The 2012 census revealed a total of just 22 pairs holding territory around Doncaster, giving an estimated total of 22-25 pairs. The earlier 1994 census showed there to be 26-28 pairs. With the same caveat mentioned for RP above about year to year variation, the indications are that in just under two decades, the local breeding population of LRP appears to have fallen away fairly significantly.  The species’ former stronghold, along the corridor stretching from Bawtry north to Hatfield Woodhouse, which used to contain the district’s main commercial sand and gravel extraction workings now holds far fewer breeding pairs. Former colliery spoil heaps have been landscaped with fewer slurry pools left, again reducing the available breeding habitat.     
I am very interested in readers’ views as to the factors involved, so please let me know what you think.
The Doncaster Bird Census 2012 did not address issues such as breeding success rates ( ie did the pairs actually rear young to fledging stage), and what factors may be influencing these rates. Land use changes, disturbance, weather (ie flooding or drought) and the effects of predation ( undoubtedly a problem particularly from Corvids)  are undoubtedly all playing a part. There is no doubt that it is a real struggle for most waders around Doncaster to achieve breeding success.
There are many sources of information on population trends for breeding birds in the UK.  Once we reach the last of the species (currently waders, next raptors and then some other key species) in this website article series,  I will include a table to show the population size percentage increases and decreases for the Doncaster district from the 1990s to 2012, and compare these to what is know from national surveys undertaken by the BTO, RSPB and others.   
Nick 
17th December 2012
Part 4

Redshank

Results in so far show that 25 pairs were counted in the summer of 2012. With a few study areas still to report, I would estimate that the district population is around 26-30 pairs.  This total therefore matches the estimate made in the 1994 survey of the Doncaster district.

Whilst the overall breeding population appears stable, there does appear to have been a slight shift in distribution, with the eastern part of the district doing less well than in 1994, whilst the western part has seen an equivalent growth.  Old Moor and the Adwick washlands accounted for two thirds of the total district population in 2012.  In contrast, the Idle Valley saw no pairs breeding – for the first time in living memory. The species is nowadays doing less well in its more natural water meadow habitat, and is clearly a species that benefits from the conservation work done at the district’s nature reserve.   

Snipe

It was pleasing to note that some 12 ‘drumming’ birds were noted in the 2012 census around Doncaster. With none of the areas yet to report being known haunts of Snipe, we can take the 12 as being the total. I had thought that we might possibly even draw a blank, and that the species was set to be extinct as a breeding bird around Doncaster. But whilst there was a positive note to the 2012 results, it is still sobering to note that in 1994 the census produced an estimate of some 32-34 ‘drumming’ birds.  In the late 1970s, there were upwards of 100 displaying Snipe in spring around Doncaster, and older birders will know that even that number is believed to be fraction of the numbers that formally bred in the early part of the 20th century.  So, whilst the species clings on, and can hopefully maintain a breeding presence around Doncaster, the scale of the population reduction is quite startling.  The sight of a drumming Snipe around Doncaster is something to be cherished.

Again as with Redshank,  the western part of the district accounted for the bulk of the breeding population with Old Moor and the Adwick Washlands holding over 90 percent.  Just one drumming bird was noted in the district east of the A1 motorway.  

Again, I would welcome readers views as to the factors behind the changes.

…………………Next week we conclude the breeding waders with Curlew and Avocet, two species which have had an amazing reversal of fortunes around Doncaster in recent years and reveal a surprise as to which was the more numerous in 2012.!

Nick 

Part 5

Avocet

In 1971 when I joined the DDOS, Avocets were  considered by most local birders as ‘dream birds’,  featuring on celluloid along with Marsh Harriers and Bitterns at the annual RSPB film show at the Grammar School ; species that fired the imagination of trips to East Anglia.  It was fanciful in the extreme to believe that one day Avocets would breed in the Doncaster district. But gradually of course, as we all know, many years and much conservation work later, and aided by an expansion of the UK population northwards, Avocets became annual visitors to the district, and then just 5 years ago bred for the first time at Potteric Carr.  How things can change in ornithology.

In 2012, no less than five Doncaster district locations held breeding or territorial pairs of Avocets, with 20 pairs in total. Not all were successful, for a variety of reasons, and whether this population level will be sustained remains to be seen, but this represents an astonishing ascendency for such a crowd pleasing wading species.

Curlew

Doncaster’s small lowland breeding Curlew population is perhaps something of a vestige of former times when there was much more suitable and undisturbed habitat in and around the district. In 1961 the breeding range came within 2.5 km of the town centre, and there were 32 pairs at 20 sites in the DDOS census of that year, though this was considered later to have been a conservative estimate of the numbers actually present.  The 1994 census revealed 33 territories, superficially similar to the earlier survey, but many fewer sites involved, and with a retreat to the outer fringes of the district, particularly to the north-eastern sector. I wrote then that “it is likely that the breeding population will slowly decline…… little, if any help appears to be on hand to assist the species to survive, apart from its own inherent resilience and longevity”. 

So far for 2012, and with a few key study areas yet to report, just 12 pairs were found to be holding territory in the Doncaster district ( all east of the A1) , and even some of these were held only briefly, before the birds moved on, unsuccessful in their attempts to settle and rear young. In fact very few birders have seen Curlew with young around Doncaster in recent years. So, whilst it is something of a ‘guesstimate’ for this interim report only, I would extrapolate this to give a district breeding population of 15-20 pairs.   

This is clearly one of our ‘red alert’ local species. As ever, I’m interested in the views of local birders on the factors involved. Habitat loss, mainly through farming and land use changes (less rough grassland, more paddock-like grazing), and human disturbance are thought to be prime reasons. Hopefully Doncaster’s lowland breeding Curlews are not set to follow the trend of their Slender-billed relatives on the Russian steppe towards extinction. 

Spring and early summer visits by birders to the remoter parts of the NE sector of the district are encouraged so we can monitor the situation more closely and regularly.   

Common Sandpiper

There were no reports of breeding Common Sandpipers around Doncaster in 2012. The 1994 census total of 5 pairs was the highest on record for one breeding season, and the species seems set to remain a rare and only intermittent breeder in the district.

That concludes the waders for the website interim update on the 2012 census. A more detailed write up will take place in due course. Thanks go to all the volunteers who worked their allotted study areas so thoroughly. 

………………..Next week we move on in the website series to look at the interim results for the district’s raptors and show that it is not just the waders that have seen significant changes in local populations. 

I am grateful for the feedback received so far – please keep it coming in. Using the website to generate debate and opinion is proving an interesting method, and is helping to build a more comprehensive picture of how certain key species are faring in terms of local breeding populations and distribution.    

Best wishes for the New Year – I will soon be asking for help from volunteers with the 2013 census, focusing on a different list of species. 

Nick 

4th January 2013

PART 6

The series of interim reports from the Doncaster Bird Census 2012 continues with a focus on the district’s raptors. 

This week account features the woodland breeders, Sparrowhawk and Common Buzzard.

Sparrowhawk

Following the national population crash in the 1950s-60s associated with the use of organochlorine pesticides, Sparrowhawks began a slow but steady recovery as a breeding species around Doncaster, particularly through the decade or so from the late 1970s through the 1980s. By 1983 there were thought to be over 20 territories in the breeding season.  In the last full census conducted by the DDOS in 1995, the population was estimated at 40-50 pairs. 

In 2012, the work of the volunteers produced a count of some 59 pairs. Extrapolating this for areas yet to report and those not covered, and also attempting to factor in some moderation for study area boundary overlap, gives a best estimate of some 50-65 pairs.  Clearly the Sparrowhawk is well established around Doncaster as a fairly common breeding bird, and may now have reached a maximum population size for the available habitat. Nationally there has actually been some slight decline in the population in the last decade, again suggesting the district’s population has already peaked. 

Common Buzzard

It is believed that reduced persecution and improved breeding success due to the recovery of the rabbit population are the key factors behind the significant UK Common Buzzard population increase which occurred throughout the 1990s across central and eastern England. The Doncaster district benefitted from this national increase, and what was an uncommon and non breeding species in the 1970s had become much more frequently observed in the decade or so before the millennium. Breeding was first thought to have occurred in the modern era within the Doncaster district in 1993 in the Kings Wood (Roche Abbey) area and by 2000 the district population was thought to be in the region of 10-20 pairs.

2012 was the first year of a full census for Common Buzzard around Doncaster and this revealed an astonishing increase in the district’s population with some 58 territorial pairs counted.  After applying similar estimation considerations as for Sparrowhawk, I would suggest that the Doncaster district breeding population stands at approximately 50-65 pairs. 

Given that there are also non-breeding birds within the district, the actual numbers of individual Common Buzzards within the Doncaster district at certain times of year is probably in excess of 140 birds.    

Such a situation would have seemed incredulous to a Doncaster district birder of the early 1970s.     

………………. Next week in the series, I will report on the falcons; Kestrel, Hobby and Peregrine, giving the latest results. For reasons of bird welfare and protection, hopefully well understood by birders locally, the information provided for the rarer species will be limited to very much of an overview.    Best wishes for 2013,  Nick  

14th January 2013

Part 7

This week we continue the interim assessment of the Doncaster Bird Census 2012 with a focus on the three falcon species known to be breeding within the DDOS area.

Kestrel

Reg Rhodes wrote in his Birds in the Doncaster District (1988) that the Kestrel was a “fairly common breeding resident”, being “as numerous as at any time during the century”.  The Doncaster Bird Census in 1995 went further and quantified this assessment, suggesting a breeding population of between 90-100 pairs within the 10 mile radius of the DDOS recording area. 

In our 2012 census the count reported was 77 pairs. Extrapolating this for suitable habitat in the study areas yet to report and those not covered, suggests that there are in the region of 80-95 pairs in the district. 

Since the mid 1980s, most national surveys show that the English population has fluctuated without a long-term trend being apparent. It is difficult to say with any degree of certainty whether our results really do indicate the local population has actually fallen a few percentage points in the last 17 years or whether the differences are simply part of the wider long term fluctuation. It may be more prudent to say that the population has changed little since the last census, though it may have decreased just slightly. So, Rhodes’ assessment of the status of the Kestrel around Doncaster remains broadly true today.  

Hobby

The Hobby was first proven to have bred successfully in the Doncaster district in 1991, though the regular presence of adult birds throughout summers for a nearly a decade prior to then in certain parts of the district may indicate that it had actually colonised as breeding species a few years earlier. 

The fieldwork of the 2012 census indicates that the DDOS area held 10 territories, giving an estimated population of 10-12 pairs.  

The Hobby’s distribution has spread markedly northwards in the UK since the 1970s, possibly due to increases in one of its main prey types (dragonflies) and to a decreasing dependency on its traditional heath land habitat, though the factors involved are not fully established.  There are currently believed to be over 2000 pairs nationally.  

Clearly to provide this dazzling but secretive species with the best protection and secure its future locally, we all need to ensure that vigilance and confidentiality are maintained with regard to details of the breeding distribution.  

Peregrine

The Peregrine was first recorded as breeding successfully around Doncaster in 2000. 

In 2012, two pairs bred successfully.  In addition, two other locations held non-breeding birds throughout the summer, suggesting there may be between seven and ten birds of various ages hunting across the district throughout the summer, even prior to the appearance of fledged young.  

There are currently around 1500 breeding pairs in Britain. In 1962, there were just 68 pairs. Such a significant increase is largely thanks to improved legal protection, more enlightened use of chemicals in farming and the species own ability to come up with creative ideas for nesting sites away from their usual haunts on the rocky sea cliffs and uplands of Britain’s north and west. 

With no natural habitat for breeding locally the species is reliant on man-made sites, at least three of which have been utilised in the last decade – concurrently in some of those years. Coupled with an abundance of its favoured prey types (mainly Woodpigeon), this terrific falcon looks set to continue to stoop and conquer and maintain its foothold in the district.  Sensible vigilance and confidentiality are again required with regard to breeding localities. 

………………..Doncaster birders of the 1950s, 60s and 70s would surely have thought it inconceivable that such avian shooting stars as Hobby and Peregrine would have flashed across the district’s skies in the numbers now being noted.  

 

………………..Next week we round off the raptors with a look at Marsh Harrier and mention in passing the short lived episode of Goshawk, in both instances preserving any restricted information.  Then we move on in the series to key species such as Turtle Dove, Yellow Wagtail, Willow Tit, Wood Lark, Tree Sparrow and Corn Bunting amongst others.   Nick 

PART 8

22nd January 2013 

Goshawk

Not unexpectedly there were no reports of Goshawks holding territory in the district in the Doncaster Bird Census 2012. But mention is made here as part of this series, and in very general terms only, of a fairly recent and short-lived episode with regard to Goshawks within the Doncaster district. The contents of the note have been agreed with the consent of birders most closely associated with monitoring the situation. 

During the period of 1997 to 2008 inclusive, one and occasionally two adult birds of both sexes were seen in an undisclosed part of the district. Display was noted in the early spring, though most sightings were of birds soaring rather than in true characteristic display. Successful breeding was not proven.  In an endeavour to secure the birds the best protection, information about the birds’ presence was restricted and the matter was withheld from publication. The frequency of observations since the end of that period then became much more sporadic suggesting the birds were not able to become established.

In Britain regular breeding had ceased by the 1880s, largely as a result of deforestation and intense persecution. Goshawks were re-introduced into Britain by falconers from the 1960s through a combination of deliberate and accidental releases. Small widely scattered breeding populations were established and numbers increased. There are currently some 400 pairs nationally and it is believed this number could potentially grow quite significantly, as the species can prosper in a variety of woodland types and sizes in lowlands and uplands. But persecution (from both egg collectors and unscrupulous game keepers) remains a problem, despite the fact that in Britain the species has the highest level of legal protection – with no landowner or their agent being exempt. 

Nick

PART 9

23rd January 2013

Marsh Harrier

In 2012, a pair held territory and nest building occurred at an undisclosed site in the district. Regrettably the pair was not successful and it is believed that the nest was    ‘washed out’ in one of the wettest summers on record.

A number of other individuals of various ages and of both sexes, perhaps some 2-3 birds in total are also thought to have remained in or visited various well watched locations within the district throughout the spring and summer months of 2012, with sufficient regularity for them to be considered as ‘summering’ in our area, rather than as passage visitors.

The occurrence of summering Marsh Harriers in very low numbers around Doncaster became established in the first few years after 2000. I am grateful to Mark Lynes for the following summary:  “this culminated in the first successful breeding at an undisclosed site in 2004 when two young were fledged, though in the preceding year a male held territory and built several nests. Breeding was again suspected in 2005”. To protect the birds’ best interests and to respect landowner wishes, the matter was sensibly not circulated widely amongst birders and was not committed to publication.

The Marsh Harrier almost died out as a British breeding species in the mid 20th century, but has recovered since the 1960s and changed its behaviour along the way, nesting in areas of farmland as well as its traditional reed bed habitat. Many individuals now stay in Britain for the winter.

The Doncaster district has clearly benefited from this national trend, probably most directly from an overspill of the Humber estuary population. Clearly further opportunities for breeding are likely to occur in future years around Doncaster and this will require sensible vigilance and confidentiality to be maintained as well as close collaboration with farmers and land managers.

 

………….. For the remaining weeks of this series on the Doncaster Bird Census 2012, we look at a number of open countryside species, many of which are known to be on the decline nationally. So next, perhaps the evocative sounds of spring and summer  are made by the Cuckoo and Turtle Dove – but for how much longer around Doncaster?

2nd February 2013

Part 10 

Two bird species whose songs are so evocative of spring and summer are those of the Cuckoo and Turtle Dove.  What did 2012 Doncaster Bird Census suggest about their current local populations?

Cuckoo

The 2012 census count indicated that some 23 male Cuckoos were holding territory in the Doncaster district, and extrapolating this for parts of the district not covered, suggests there are around some 25 to 30 males.  This compares to an estimated 130 males in the DDOS census of 1995, representing a reduction of some 77-80% in the last 17 years. 

National census work shows that Cuckoos have been in decline since the early 1980s, especially so in England and Wales, less so in Scotland.  The declines have been of the order of 50 to 70 per cent depending upon habitat type and how well its host species such as Meadow Pipit are faring. Other factors such as decreases amongst certain British moths may have reduced food supplies and the species may also be suffering difficulties on migration and in winter quarters.  New GPS tracking methods are being used to help understand the complex movements of the species.  

The situation in the DDOS area appears to mirror what is happening elsewhere in England. We will need to keep up the close monitoring of our local Cuckoo population, particularly once the initial spring wave has moved through and we are left in late May and early June with those that remain to attempt to breed.    

Turtle Dove

National census work shows severe declines in Turtle Dove abundance, beginning in the late 1970s and continuing to the present, with losses estimated at anything between 70% and 90 %. The species is also one of the most strongly declining bird species across Europe. 

Unfortunately it has come as no surprise to learn that in our census during the summer of 2012, just 12 pairs were found holding a breeding territory in the DDOS area.  Even accepting that there may be the odd pair in areas not covered (and giving an optimistic estimate at the very outside of 15-20 pairs for the whole district), the situation is alarming and represents one of the most significant declines of any species in the DDOS area since modern recording began in the 1950s.  The 1995 census estimate was of some 140-150 pairs around Doncaster, meaning the decline in the intervening 17 years is of the order of around 86%. Doncaster birders with memories stretching back  to the early 1970s or even further to the 1960s will recall how relatively common Turtle Doves were, with post breeding gatherings sitting on wires over suitable farmland in the early autumn.  

Most well watched birding sites around Doncaster still manage to secure a sighting for their ‘year lists’, usually from the odd passage bird, but for how much longer?   Sadly, it is perhaps no exaggeration to say the species appears to be heading for localised extinction as a breeding bird.  Obviously we must all share the hope that we do not loose this quite stunningly beautiful dove and its lovely ‘purring’ song from our wild hedgerows. 

……………. Next week we continue with a few more from the list of species covered in the 2012 census.    Nick  

Part 11

6th February 2013

Willow Tit

Just 18 pairs of Willow Tit were found in the DDOS area in the census of 2012. Most of the known breeding locations were covered, so this figure requires little extrapolation and at best the district’s population would appear to be in the region of 20-25 pairs.  (Another 5 pairs were found on Thorne Moors, just outside our census area). 

The situation locally has been most intensively studied by Dave Carroll, Sue and Roger Bird and fellow birders at Potteric Carr, one of the district’s strongholds for the species. They have reported a significant decline in the last few years, with a particularly sharp fall from seven pairs in 2011 to just two pairs in 2012.  Data from ringers at other sites in the district indicates a similar downward trend, and whilst we have no previous DDOS-wide survey with which to make comparisons, it is clear the local population is now only a fraction of what is was say 20 years ago. 

Willow Tit is a red‐listed Bird of Conservation Concern, with estimates showing a reduction in the population of around 95% in the UK over recent decades. A number of reasons for the national decline have been suggested though the cause is not yet fully understood. Such is the concern for this species’ decline that it has been added to the Rare Breeding Birds Panel (RBBP) list of birds monitored.   

Clearly we need to note all observations of Willow Tit and ensure records are submitted to the DDOS recorder via Comments on Doncaster Birding, by email to Sabsgull@hotmail.co.uk or any other method more suitable. 

7th February 2013

Part 12

Wood Lark

16 pairs of Wood Lark were found in the census during the summer of 2012. The species returned to breed in the Doncaster district in the mid 1990s after an absence of nearly four decades.  Since that re-colonisation which occurred by just a hand full of pairs, the population in the DDOS area then grew to around 25 pairs by the early 2000s.  There has without doubt been a slight easing off in numbers this last decade, as reflected in the current levels.  

The Wood Lark requires substantial dry areas of bare well drained ground or very low vegetation for foraging, with good rabbit numbers helping to maintain the structure of vegetation required. The species is known to respond opportunistically and rapidly to the creation of new habitat. Fire damage, wind damage and rotational felling help to create clear areas in conifer plantations. Equally, the birds are quickly displaced when clear areas grow up again.   This is believed to be the case in the main coniferous woodland in the south of the district, where only 1 pair held territory in 2012, compared to 7 pairs ten years ago.  Fortunately the species uses a good variety of habitats throughout its DDOS haunts, and so hopefully we can look forward to hearing its wonderful song for many years to come near Doncaster. 

In many ways Wood Larks are our earliest returning summer visitor, with birds back on territories by mid February usually.  Not long to wait then …      

Skylark

The result of any survey depends heavily on census technique used.  For those species breeding at low densities, the simple “look-see” method, which we asked volunteers to use in the 2012 Doncaster Bird Census, gives very reasonable results. Fortunately, because most of the species involved in the 2012 census breed in relatively low numbers, we can say our estimates are fairly sound. But scan the fields and try to estimate how many Skylarks may be singing at any one time, and it starts to become much more difficult to assess population levels. Different techniques need to be used.   So the results given here can only be said to be at the very best just rough approximations.

Some 1400 pairs of Skylark were counted in the study areas covered by the 2012 census.  Extrapolating this for the rest of the district, suggests a population of at least 2500 pairs. Interestingly in the last survey in 1994, using the same technique, however flawed, the estimate was of some 2500-4000 pairs in the DDOs area.  

Focusing in specific study areas for direct comparisons is interesting and this will be provided in the fuller write up of the census in due course. Three examples are worth noting though. In Study Area 17 (which includes Potteric Carr and environs) there were 26-30 pairs in 1994 and just 10 pairs in 2012. In Study Area 19 ( which includes the land within the boundary linking Bawtry-Tickhill-Loversall- Bessacarr, i.e. land south of Potteric Carr), there were some 120 pairs counted in 1995 and 80 in 2012. In Study Area 21 (the Idle Valley) some 200 pairs were estimated in 1995, and 150 in 2012. So even when not using the correct survey technique for a certain species (as here with Skylark), some useful information about the comparative declines that have taken place is discernible.   Not great science I know, as the correct technique should be used at the outset, but the results are not without interest.     It is without doubt that overall our census will have

underestimated the actual number of breeding population of Skylarks in the DDOS area. This remains difficult to gauge, but my best guess is probably well over 3000 pairs. 

National census work seems to show that the UK population is believed to have declined by anything between 15 and 25 % since the mid 1990s.  The most likely cause of the decline is the change to autumn sowing of cereals. This practice restricts opportunities for late-season nesting attempts, because the crop is by then too tall. Birds do better in areas with extensive winter stubble. Leaving small, rectangular patches of bare ground (‘Skylark plots’) within autumn-sown cereals appears to provide many of the benefits of spring-sown cereals at very low cost to the farmer. 

It seems likely that the district’s Skylark population whilst still strong has followed the national trend and declined in the last 17 years. 

10th February 2013

Part 13

Tree Pipit

Just 13 pairs of Tree Pipit were found in the DDOS area in 2012, and all were within the Hatfield Moors study area. Another 4 pairs were on Thorne Moors, just outside of our census area.

Former haunts such as Bawtry Forest drew a black in 2012, probably because the clearings were too overgrown. Whilst this can change from year to year, it seems the only reliable site annually in the district is now Hatfield Moors. 

In the Doncaster Bird Census count of 1998, there were some 29 pairs, comprising 14 on Hatfield Moors, 13 in Bawtry Forest and 2 in the Idle Valley (Barrow Hills).  

Since the mid 1990s there have been significant declines in the Tree Pipit population in England, of at least 30%.  The causes are unclear, but may be linked to changing forest structure. There have also been recent reductions in many north European countries.  

Clearly we will need to monitor the situation closely in the DDOS area. Tree Pipits winter in Africa south of the Sahara and return in mid to late April. It is always a lovely sight to see them parachuting down after launching from their high song posts. 

Meadow Pipit  

Some 210 pairs of Meadow Pipit were counted in the DDOS district in 2012. Extrapolating this for a few suitable study areas not covered or yet to report gives a best estimate of some 230 to 280 pairs. 

There was also a significant concentration in the Hatfield Moors are, which accounted for nearly half of the district count. Away from this mainstay, the local population seems to be scattered very patchily in small clusters across the district, favouring the ranker grass bordering river banks and former gravel and colliery workings.    

The 1995 Doncaster Bird Census suggested a district wide population of up to 350 pairs, so there has been a slight decline in the intervening 17 years, one which appears to mirror the downward trend apparent in national census work across lowland England.  

Meadow Pipits are classed as partial migrants and conditions on the main Iberian wintering grounds have been linked to the decline, as have losses of marginal land from parts of the breeding range. We are not clear whether our local breeding population moves as far south as Spain in winter or whether some of the population stays nearer home. We certainly have Meadow Pipits over wintering, but these could be from further north. We have gradually over the years lost much rough grassland around Doncaster, so there is no doubt that habitat loss and change is a key factor affecting our Meadow Pipit .  

Yellow Wagtail

Approximately 225 pairs of Yellow Wagtail were counted in the DDOS district in 2012. Again extrapolating this figure for suitable study area not covered or yet to report suggests a district population of some 250 to 280 pairs. 

Most birds are found on farmland (rather than in the margins of marshland, although the proximity of drains and water seems to help) where they favour various crops such as wheat and peas. 

The 1995 census suggested that the Doncaster district population was of the order of some 340 pairs, so our current estimate seems to indicate the species has declined by around 20% in the intervening years. Yellow Wagtails have been in decline since the early 1980s according to national survey work (reducing by over 40% since the mid 1990s – hence more so than around Doncaster), and after a shift from the green to the amber list in 2002, the species has now been moved to the red list. Various reasons have been suggested, including farmland drainage, the conversion of pasture to arable land, the change from spring to winter cereals, and the loss of insects associated with cattle.  

The European trend, which includes other races of the species, has also been strongly downward since 1980. Britain holds almost the entire population of the distinctive race flavissima, and so population changes in the UK are of global conservation significance. Yellow Wagtails winter south of the Sahara, and so when we are looking at a Yellow Wagtail around Doncaster this spring and summer, it is worth remembering that not only are we looking at a stunningly beautiful bird, but a very special national sub species and one which, even after recent reductions, still has a reasonable presence around the DDOS district.  

 13th February 2013

Part 14

Corn Bunting

Approximately 75 male Corn Buntings were counted singing on territories in the Doncaster district in the summer of 2012. Extrapolating this for suitable areas which received no coverage or are yet to report suggests a best estimate of some 90 – 110 territories for the DDOS area. 

This is a significant reduction (down approximately 70%) on the 1995 Doncaster Bird Census in which 365 males were counted and the population was estimated at 380 – 400 territorial males.     

Corn Buntings can be polygamous, the best counting unit for census work being the singing/territorial male. The males defend territories from mid April to late August, with the females (noticeably smaller in size) arriving up to two months later and occasionally forming small flocks.  We seem to see fewer Corn Bunting flocks (either in mid winter when the sexes mix, or the spring female flocks) around the Doncaster district these days, another indication perhaps, unless there is much movement, of the decline that has taken place locally.    The species has an attraction to areas with a good acreage of barley, though areas with a mix of cereals (including barley) and other crops do best. 

More on the DDOS distribution in the fuller write up, but the species exists in well scattered colonies that seems to have become more fragmented in the last 17 years. Despite the reduction and thinning of the distribution of the Corn Bunting population around Doncaster, the district still remains one of the better regions to see the species within Yorkshire.

The Corn Bunting is now assigned as ‘Red’ in the UK Conservation Status, following steep declines in the last quarter of the 20th century in which time it withdrew from large areas of its former range. The decline was greatest in the 1980s, but continued thereafter with a 30% reduction since the mid 1990s. The DDOS decline of around 70% in the last 17 years has therefore been even more dramatic, though we need to be cautious in relying too much on one year’s data set (as we do of course with any of the species covered in this series). The species has been intensively studied at national level. Many factors are involved, with a key factor believed to be agricultural intensification which is producing reduced availability of both winter seed and summer insect life.  

Clearly we need to monitor the species closely from now on. Calm, balmy mid summer evening walks out along some of our more remote bridleways that cross cereal farmland are always worth the effort. 

16th February 2013

Part 15

Yellowhammer

As has already been mentioned when reporting on our Skylark results, the technique used in any census needs to be tailored to (amongst many factors) the relative abundance of the species being surveyed. Once a species is above a certain density, the simple “look-see” method has real limitations and produces estimates with very wide confidence levels.So what follows is only a very general estimate of the situation around the DDOS district regarding Yellowhammer.

Some 750 pairs of Yellowhammer were counted in the census of 2012 around Doncaster, and extrapolating this for suitable uncovered areas, gives a district wide figure of at least 1200 pairs.The Doncaster Bird Census of 1995 using the same methodology, and many of the same volunteers, suggested a population of some 2000 pairs.Personally I believe the methodology has produced underestimates for both years and totals of 3000 or more in 1995 and 1800 or more in 2012 are more likely. In 2012 some study areas singing males were holding territory at a density of up to 8 – 10 per square kilometre, making it one of our commoner open countryside birds in certain parts of the district.

But however flawed the survey technique, the relative decline in abundance around Doncaster between 1995 and 2012 is still noteworthy. This was of the order of approximately 40% and is actually greater than the reductions noted in national census work since the mid 1990s (20% or so). Breeding densities for Yellowhammer are known to be correlated with hedgerow length, but many factors are thought to be involved, with farming techniques and land use changes again seemingly at the heart of the issue.

Despite the falling population though, the species remains very obvious throughout much of the district. Walks on calm evenings in summer, even into early July when most other species have ceased singing, usually produce a good show of these birds, and make such walks even more enjoyable.

Reed Bunting

Slightly easier to survey than the former species but with the census technique used still not being quite right for this species, we nevertheless managed to count some 460 territorial males in the summer of 2012. Extrapolating this for suitable uncovered areas suggests a population of 850 or so pairs.I would raise this up a few percentage points, and put the population at some 1000-1200 or so pairs in the DDOS area. We have no previous Doncaster census with which to make comparisons, and so the 2012 data provides us with a benchmark for future reference.

Whilst the traditional reed bed and wetland habitats remain its primary breeding habitat in the district, the Reed Bunting also appears to do well in crops of oilseed rape. It is also shown in national studies that farmland densities are four times higher in oilseed rape than in cereals or set-aside and that this crop is crucial in reducing the dependency of the species on wetlands. The species appears to have widened its breeding habitat niche out of wetlands, much as Yellow Wagtails have done, though into a different crop type.

National indices show the species declined rapidly during the 1970s, but also that Reed Bunting abundance has subsequently remained remarkably stable. In recent years, national results even show a significant population increase. The initial decline placed Reed Bunting on the ‘red list’ but in 2009, with evidence of some recovery in numbers, the species was moved from red to ‘amber’. With very high acreages of oil seed rape around Doncaster, and plenty of protected wetlands, the species look set to continue to do well in future.

……………………..it’s getting very near the end………………………………………………

just Tree Sparrow and Raven to finish the interim accounts in this series.After that I will do a short summary in tabular form of each species we have covered, as well as importantly acknowledging all the volunteers who contributed to the census in 2012.

I’ve had some terrific feedback (please keep it coming in, comments and critique welcome), which has added considerably to our knowledge and built on the information from the census itself. Many of the species ‘interim’ accounts in this series will now need revising. Eventually the census will be written up with a little more scientific discipline as a paper (and grammar all correct!), with more detail on the various study areas that make up the DDOS district.But the series has achieved its purpose of increasing our collective understanding of the populations and distributions of certain key bird species around the Doncaster district.I hope too that website readers have enjoyed the series over the winter, and been stimulated to take part in future survey work.

With spring now just around the corner, it will be time to announce the list of species which we will cover in the spring and summer of 2013 and to seek out volunteers to yet again help cover as many study areas as possible. Despite all the land changes and challenges that face our breeding birds, the Doncaster district certainly still does exceedingly well. Nick

18th February 2013

PART 16

Tree Sparrow

180 pairs of Tree Sparrow were counted in the study areas covered during the 2012 Doncaster Bird Census. Carrying out our usual extrapolation for uncovered study areas with suitable habitat, a reasonable district estimate would be in the region of 250 – 300 pairs, and therefore on a par with the estimate made in the last district wide census in 1995.

The population around the DDOS is sparingly distributed, occurring in small widely scattered locations and comprising small colonies of between one and a few pairs usually associated with farm outbuildings.  The species can breed quite unobtrusively, and given the increase in security around farms these days, it is quite possible we are overlooking them in less well birded parts of the district. More on the distribution of the species within our 10 mile radius recording area in the fuller write up, in due course.

Tree Sparrow abundance crashed spectacularly in the UK between the late 1970s and the early 1990s. There has been an increase since 1994, but it is thought by the BTO and RSPB that for every Tree Sparrow today there were perhaps around 30 in the 1970s and any recovery therefore has a very long way to go. Agricultural intensification, and particularly the reductions in winter stubble, is thought to be a major cause of the decline.

Tree Sparrows in the UK are mostly fairly sedentary but there is more dispersal of juveniles and movement between breeding and wintering areas than there is for House Sparrows. When population levels were higher, there were a few reported exchanges between the UK and countries on the other side of the North Sea, with Spurn Bird Observatory contributing many of these records.

Overall, the population around Doncaster overall does not appear to have made any discernible headway since what should have been (if we are in line with national trends) an historic low in the 1990s. Clearly the provision of winter food and nearby nest boxes at some of the district’s nature reserves have helped in the species survival, particularly near wetlands as the adults favour aquatic insects for the nestlings. But it seems it is highly unlikely that the population levels of the 1960s will return for the foreseeable future – and possibly if ever.  But birdwatchers can play a part, by looking out for Tree Sparrows in new areas and trying to persuade land owners to create the conditions in which this new nucleus can turn into a successful breeding population.

 

22nd February 2013

PART 17

Raven

In his book ‘The Raven’, Derek Ratcliffe asserts that the Raven “is a bird which – perhaps more than any other – has been invested by humans with symbolic meaning and legendary mystery.”

Arguably the most intelligent of native British birds, the Raven’s supposed cunning and wily nature has led to it becoming steeped in myth, legend, folklore, and history of which perhaps the most commonly known superstition is its association with the Tower of London and the security of the Crown.

In the middle ages the Raven was a common inhabitant of our towns and cities, living off refuse and discarded food. Such was its reputation for cleaning up that it was forbidden to shoot them, with payment of a penalty to the Crown.

In the UK, historic persecution of Ravens by farmers and gamekeepers caused a rapid reduction both in their population and range by the 20th century. However, thanks to a decrease in this activity, as well as and changing attitudes of landowners and farmers, Ravens have begun to recover to normal population levels in the last quarter century. In the UK the Breeding Bird Survey shows that from 1994 to 2007 the Raven population increased by 134%.

Ravens are omnivorous scavengers and predators. Their diet varies greatly; although full-grown birds occasionally form part of their diet, these are thought to be more often scavenged than predated.

Ravens are amongst the earliest nesters of the UK bird population. They pair for life and, prior to mating, they perform fantastic tumbling display flights to reinforce their pair bond. They have a typical ‘croaking, cawing’ call, but are also fine mimics, and have a huge vocal range.

In 2012, two pairs of Raven nested within the DDOS area, with the pairs successfully raising two and three young. Site details are not being disclosed in this series. I am grateful to Chris Johnson for the following summary of his paper in the DDOS Lapwing Species Series, edited by Martin Limbert: “…. Ravens were first seen as singles in May 2002 and June 2003 then a pair intermittently from Sept 2003 through 2004, with breeding first occurring in 2005 ”.

The birds are only infrequently seen away from their regular haunts in the district. But whilst there will be some dispersal of the young away from their birthplace, some undoubtedly remain locally. The actual number of birds present within the DDOS area is not known, but it is suggested it could be in the region of some 6 -12 birds.

   ………………. that concludes the species accounts in this interim update on the Doncaster Bird Census 2012.  Next week a short summary of the latest picture of all the species covered, with some revised population estimates based on feedback received from website readers as the series has been running through the winter.  I would also like to list all the volunteers who helped with the fieldwork, and who I hope will join in again in 2013. It would be excellent if we had some more volunteers in 2013 – the species to be covered to be announced next week also. Nick


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November 23, 2017