Monday, 30 December 2013

End of Year Review, December 2013

So here we are at the end of my third full year writing this blog, I hope you have enjoyed its content and would like to thank all those who follow it and those who have visited over the years. This year (2013) has been an interesting one for me as back in February I started a new job, which I had hoped would give me more spare time to enjoy bird ringing and other natural history activities. In reality, more spare time meant more out of work social commitments, which did limit the amount of free time I had, and three stints in hospital were certainly not welcome. Despite the set backs I still had a great year which resulted in several new birds in for me in Hampshire, over 20 new moth species in the garden, a couple of new birds in the hand and ended with a British tick (Brunnich's guillemot). In typical fashion for a year end post I thought I would do a quick summary of my personal highlights of the year, and please feel free to share yours with me.

The start of the year for me was all about trying to see as many bird species as possible on the patch. There were no real highlights to speak of with this, that came in the form of a recovery notification from the BTO of one of the common nightingales that I had ringed at Botley Wood. Unfortunately the bird was found dead in France 488 days since being ringed, which was not good news for the bird, but was my first foreign control of this species since starting the project.

Adult Common Nightingale - Sadly found dead in France

The long staying and very confiding black-bellied dipper at the BTO HQ Thetford in Norfolk was the first that I had seen in the UK, and got my annual Norfolk pilgrimage off to a good start.

Black-bellied Dipper - Norfolk

Eurasian siskins came into my garden in good numbers this year and I ended with a record number of 40 new birds ringed, beating the previous best of 12 back in 2003. Individuals were trapped throughout January, February, March, April, May and one bird was re-trapped in August. The peak month though was March when 22 new birds were ringed.

Male Eurasian Siskin

The return of the common nightingale is always a highlight for me and this year was no exception. At least eight singing males were back on territories, and I managed to catch four of those, one being a bird from May 2009. This month was also memorable for the presence of a singing male common redstart and a lesser spotted woodpecker, both found whilst surveying for nightingales.

Retrap Adult Nightingale - Botley Wood

Being my 25th wedding anniversary this year my wife and I took short break to the Greek Island of Rhodes. There were no new birds for me but we did have a great trip with a variety of wildlife being seen. The highlight for me had to be snake-eyed lizard which was stunning beast, the resultant blog post has become the most read post on this site. 

Snake-eyed Lizard, Rhodes

The undoubted highlight for me this year was being invited out to ring northern goshawk pulli. I had ringed common buzzards before but the size of these birds, in particular the females and their talons was amazing. The low point was being savaged by a cat and spending four days in hospital with an infected arm.

Juvenile Goshawk

Mothing really took off this month and checking the trap before work became near on impossible due to the numbers present. 
On one date I recorded 250 moths of 90 species in the garden and by the end of the year I had recorded 310 species. The second high point was surviving being knocked off my bike by a car and only needing seven stitches in a gash on my chin and having mild concussion for 48 hours.

White Satin Moth - a new species for me

Ringing was starting to get into full swing at Titchfield Haven and on 17th we ringing 223 new birds, with 24 of those being garden warblers, the most we have ever caught in one day by a long way.

Garden Warbler - Titchfield Haven

This month was memorable for two amazing highs, catching my first, and second, Clifden nonpareil moths whilst staying at Castlehaven on the Isle of Wight; and seeing the first brown shrike to ever be recorded in Hampshire. An excellent find by Bob Marchant.

Clifden Nonpareil at Castlehaven, Isle of Wight

There were many highlights during October, but these were sadly all overshadowed by the untimely death of Tim Lawman, a popular and active member of the Hampshire birding scene. The highlights were finding a yellow-browed warbler at The Hampshire and Isle of Wight Trusts (HIWWT) Testwood Lakes Nature Reserve, and then another at Anton Lakes whilst waiting for Hampshire's second ever Radde's warbler to show. The semi-palmated plover at Sandy Point on Hayling Island, a truly amazing find by Andy Johnson. And if all that wasn't enough, it ended with us catching our first, and Hampshire's third Radde's warbler at Titchfield Haven. What an autumn this turned out to be!

Radde's Warbler at Titchfield Haven

Ringing bearded reedlings (or parrotbills) at the HIWWTs Farlington Marshes reserve was a real treat, but the undoubted highlight had to be the phenomenal starling roost of 10,000 to 100,000 birds at their Blashford Lakes nature reserve. As natural history spectacles go this is one of the best I have seen and is still continuing as I write this post. If you get the chance it is definitely worth a visit and if you are lucky you may even get the see one of the two bitterns wintering there.

A Murmuration of Starlings at Blashford Lakes

There is only one contender this month and that was the Brunnich's guillemot in Portland Harbour. We were heading home after spending Christmas in Cornwall and made the short detour. A cracking bird and a British tick for me to end the year on.

Saturday, 7 December 2013

Great Tit Bill Deformity

This morning I had things to do around the house and so opened a net in the garden. The session was ticking along steadily with mainly blue and great tits, a couple of nuthatches and a goldfinch, and then I caught this...

Adult Male Great Tit with Extra Long Upper Mandible

I have caught birds with deformed bills before, and in fact have posted on this blog images of a blue tit with a deformed and crossed over bill, but this bird was amazing. The upper mandible measured an amazing 28.5mm, greatly overlapping the lower mandible, which also appeared longer than the norm. 

Long Billed Adult Male Great Tit

Given the extent of the overlap, it was difficult to image how this bird could successfully feed, and unfortunately it turned up in the net before I saw it trying. However, it had clearly adapted to its deformity, since the bird was an adult, had a fat score of 1, a muscle score of 2 and a very healthy weight of 20.4 grams. Out of interest this weight was the heaviest of the four great tits I have trapped by 2.3 grams.

Under side of Long Billed Adult Great Tit
The British Trust for Ornithology are currently carrying out a Garden Beak Watch Survey the link to which is here. There are several suggestions as to why beak deformities occur in birds, on their website the BTO state that they "could be influenced by disease or may be inherited genetically and while research continues to investigate these possibilities, current evidence is not comprehensive". Whatever the cause the result, as in this bird, can be quite spectacular and you can only admire how the individual has adapted to survive with its deformity.

Sunday, 1 December 2013

RAS Ringing at Manor Farm Museum, Botley

In the year 2000 I began ringing House Sparrows at Manor Farm Country Park near Botley, Hampshire. Initially the numbers of birds ringed was fairly modest but as more birds were ringed I decided to set up a BTO RAS project. I have previously written about the project on this blog, and it is one of the driving factors why I continue to ring birds at the site. Over the years, the numbers of birds I have ringed has fluctuated quite significantly, this has been due to a number of reasons. The main issue has been work commitments, which has limited the amount of time I could put into the project. But management practices at the site, and accessibility (the site is open to the public) have also played their part. 

House Sparrow with Inscribed Darvic Ring

Many years ago I began colour ringing sparrows as I thought that this would increase the recapture rate of the project. Sparrows are very clever and will remember a net site thereby making them difficult to recapture. I began using small plastic colour rings, but it soon became evident that the sparrows were removing them. I then started using overlapped rings, before ultimately settling on overlapped darvic rings with a letter and two numbers inscribed on them. 

Graph Illustrating Total Numbers of House Sparrows Ringed per Year (blue)
and Retrapped per Year (Red)

Since the year 2000 I have ringed 656 new birds and have retrapped 453. The longest lived individual recorded to date is 4 years 276 days, and the second longest is 4 years 267 days; there have only been three retraps of birds over 4 years during my study. According to BTO data the maximum recorded age is 12 years and 12 days, which was set in 1978, so an individual from this population has someway to go to get to that ripe old age. There have been several theory's about the decline of the House Sparrow including changes in farming practices (increased use of pesticides, cleaner farming, and changes in cropping regimes), loss of nesting sites and increases in predator species such as sparrowhawk. At Manor Farm these changes have not really occurred but nonetheless the population seems to be declining. I have witnessed sparrowhawks taking birds from a recently flailed hedge, so maybe that is the cause here.  

Ageing House Sparrows after their post juvenile/post breeding moult is not possible since the extent of the moult is complete for both adults and juveniles. I have not previously looked in detail at ageing birds, but there have been several suggestions by various authors in the past describing how to separate first year from second year birds. These include a less pure grey crown and broader chestnut edges in first year birds, a difference in the pattern on the upper middle secondary covert, and the colouration of the bill, specifically the yellow bill colour and fleshy lateral lobes at the base of the bill.

Two male house sparrows, note the all dark bill and paler check of
the left hand bird, but the yellow base and grey check to the right
hand bird

Over the last few weeks have started looking at the bill on some of the birds I have captured, although at this stage I cannot make any assessments as I am catching mainly new birds. However, in male birds I have noticed considerable variation in the colouration of the bill. This is illustrated above where the bird on he left has an all dark bill, and also a more defined head pattern and a whiter cheek. However the bird on the right has a paler bill with yellow at the base, a less well defined head pattern and greyer cheek. Unfortunately both birds were new birds so I could not confirm my suspicions that the bird on the left is an adult.

Adult male House Sparrow which was originally ringed on 2nd
January 2010 and retrapped on 30th November 2013 (3 years 332
days later)
One male bird that I retrapped this weekend was originally ringed on 2nd January 2010 (image above). Like the left hand bird in the previous image this bird had a mainly black bill, although not as dark as that bird, and a clearly defined head pattern. Interestingly this bird also exhibited a very well marked black face mask and dark lores. The cheeks are pale grey in colouration.

This male again had an ill-defined head pattern, pale horn
coloured bill with a yellow base

The image above illustrates another male bird, this time with an ill-defined head pattern and black mask, paler horn coloured bill with a yellow base. The cheeks on this individual are quite pale, but appeared slightly buff coloured as opposed to the dark billed birds which were greyer. I have yet to look in detail at female birds, but of the ones that I did the bill colour seemed to be fairly consistent, being dull pink in colouration with a yellow base. Over the next couple of years I will look more closely at this and maybe by the end I will be able to confidently separate adult and juvenile birds.

Female House Sparrow with dull pink bill and a yellow base.

In two sessions this weekend I caught 50 new birds and retrapped 12, of 10 species. The new species included 28 house sparrows, eight goldfinches, five blackbirds, three robins, two blue tits and single wren, great tit, nuthatch and carrion crow. Of the retraps the most notable were a long-tailed tit, that was originally trapped 2 years and 270 days previously, a blue tit that was originally ringed 2 years 269 days previously and three House Sparrows that were ringed 4 years 276 days, 3 years 332 days and 3 years 156 days previously.
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