Saturday 30 November 2013

Un-bill-ievable Blue Tit

It was a beautiful day today and far too sunny to put a net up in the garden until the sun moved round behind the house and put the front garden net site and feeders in shade. I put a net up at around 2:15 with the intention of catching a few more Goldfinches and the first birds were caught within a few minutes. These were a Starling, a Goldfinch and a Blue Tit with an incredibly deformed bill.

Un-bill-ievable Blue Tit
I have caught birds with deformed bills before but nothing like on this scale. Both the upper and lower mandibles were hugely overgrown. How it feeds is any ones guess but it clearly does well enough as it was a healthy adult. That makes it in the region of 18 months old at the very least but it could be much older.

The uniform blue colour of all the coverts and blue primary coverts
in particular show that this bird is an adult.
I have not seen this bird in the garden before and it wasn't a bird I had ringed previously so I don't know any of its history. It will be interesting to see if it turns up in the garden again as I would like to see how it feeds. It is always tempting to interfere and trim the bill in a case like this but I didn't and wouldn't. It is a natural deformity and ringing is all about studying birds without any undue interference.

Whichever way you look at this bird it sure looks odd.
BTO garden bird surveys have revealed Blue Tits to be the most frequently recorded species with beak deformities and you can read more by clicking here. Coincidentally a post about a Blue Tit with a deformed bill has been published recently on the BTO 'Demog Blog' and can be seen by clicking here.

Here are some of the measurements.
Ringing totals for 30/11/13 with retraps in brackets.
Goldfinch 5 (1)
Starling 1
Blue Tit 1
Robin 1
Long-tailed Tit (1)
Total 8 (2)

Wednesday 27 November 2013

27/11/13 - Keeping the light on

I have kept the moth trap running despite the cold and frosty nights of late. Whilst the moth trap has been drawing a blank I have seen a quite a few Winter Moths and possibly the odd Northern Winter Moth whilst walking the dog, even on the coldest evening. I keep meaning to take a net and few tubs with me every time I go out after dark only to remember what I should have done when a moth flutters across my path. I have caught a few of these moths by hand including one earlier tonight but each has been of the bog standard Winter Moth variety..
A slight increase in the temperature over the last couple of nights finally produced two moths in the trap this morning. A male December Moth was only the second of the autumn whilst an Angle Shades was one of many, albeit the first for a while. Not much to write about really but better than nothing. Moth catches are unlikely to get much better than this for some time but I will continue to keep the light on for a good while yet..

December Moth (Poecilocampa populi)

December Moth (Poecilocampa populi). The heavily feathered
antennae and size identify this individual as a male
Angle Shades (Phlogophora meticulosa)

Angle Shades (Phlogophora meticulosa),
looking very much like a crumpled or withered autumn leaf

Saturday 23 November 2013

When they're gone they're gone.

The berries on the Rowan trees in the garden have taken a real battering over the last week. Up to 4 Mistle Thrushes, 6 Blackbirds, 2 Song Thrushes and an increasing mob of Starlings have been regular visitors. On Wednesday morning a male and female Blackcap also put in an appearance and consumed a few of the smaller berries. This tempted me to put out the first apple halves of the winter along with a chopped peanut fat cake in the hope of keeping the Blackcaps around. Unfortunately the fat cake only attracted more Starlings.

The forecast for today was for a cloudy morning and sunnier afternoon. This would have been ideal for catching more a Goldfinches for my plumage study in the morning and then taking photographs when the sun moved round to a better position in the afternoon. As things turned out it was crystal clear first thing and clouded over by lunchtime - sods law. At least the wind remained light throughout with the ringing less affected than the photography as a result. I know I am always complaining about the light but it was very poor when the birds performed at their best. I was using ISO 1600 to 2500 in the main, lens wide open and hand held at relatively slow shutter speeds which produced some very smudgy or blurred results.

Ringing totals for 23/11/13
Goldfinch 13 (2)
Starling 5
Blackbird 1
Blue Tit 2
Great Tit 1
Dunnock 1
Greenfinch (1)
Total 23 (3)

Sunday 17 November 2013

17/11/13: Head count of 20.

A misty murky morning gave way to a plain old murky afternoon and ideal conditions for mist-netting. This tempted me to put a net up after lunch to try and catch a few more of the garden Goldfinches. I didn't have long to wait before the first birds were caught and I was kept very busy for the rest of the afternoon; recording plumage details and taking photographs of the succession of birds caught.

By the end of the afternoon I had caught 17 new and 3 retrap Goldfinches and a couple of Collared Doves for good measure. This brought the total number of Goldfinches ringed this weekend to 31 and the total for the autumn to 313, not a bad total given the size of my garden. Hopefully the number of birds ringed will produce a few recoveries in due course but the photographs and plumage descriptions are the real prize..

Side profiles of the heads of the 20 Goldfinches caught this afternoon.
Photos are also taken of at least 4 other parts of the plumage of each bird.

Saturday 16 November 2013

Talking heads

I put a net up in the garden this morning with the aim of catching a few more Goldfinches for my study of their plumage features. This involves taking descriptions and measurements of various parts of the plumage along with a series photographs of each bird. The weather was ideal for catching being dull and overcast and 14 new Goldfinches were caught during the morning.

Side profiles of the heads of the 14 Goldfinches caught this morning, one of the standard photographs
 that I take of each bird. A few still had remnants of juvenile feathers.
The majority were sexed using the usual criteria but that assumes those criteria always hold true but unfortunately they don't. Some clearly had contradictory or borderline sexing features which shows that each of the established sexing criteria are not 100% reliable on their own but that is nothing new. However, I am also starting to find other plumage features that may help with sexing birds. One thing that these photos do show is the variation in bill size and shape and that is also known to relate to the sex of Goldfinches.

The red mask of this juvenile (first winter) bird is quite extensive and extends well behind the eye (above) indicative of male. The nasal hairs appear to be quite worn but are a pale greyish white which is more indicative of female. The lesser coverts were pale brown and more like those of a female. This is one of those birds that is probably better left unsexed although I suspect it is probably a male.

The red mask of this adult also extends behind the eye (above) but is generally less extensive than the previous bird. Nasal hairs are again greyish white in the main and indicative of female. The lesser coverts were pale brown also suggesting female. Other plumage features and a short wing length also indicated it was a female. This bird was sexed as a female but the extent of the red behind they eye could lead to confusion for some.
Another male type with extensive red mask and all other features were indicative of it being a male. This bird also had a very deep bill and convex culmen compared to all the others caught today.
Hopefully my study will help throw some light on the sexing of Goldfinches using plumage features but I suspect that it will mainly find that a significant proportion of birds are safer left unsexed or are only given a provisional sex..

Monday 11 November 2013

Sparrowhawk 1 - Collared Dove 0 = me late for work.

The post title refers to the result of an encounter between a juvenile female Sparrowhawk and a Collared Dove in the garden this morning. I was just about to set off for work when I noticed the action so I grabbed the camera and managed to get a few shots through the window. The light was terrible as it was raining and really dull, nearer half light, so I had to use the lens wide open and really up the ISO. Not good when you only shoot in jpeg like me.

The game was well and truly over for the Collared Dove before I took the first shot as the Sparrowhawk had already eaten its head by then. I watched it feed for about 15 minutes before it flew up onto the hedge with the remains and then it carried them off into the trees across the road. The rather grainy photos that follow tell some of the story for themselves. A cracking bird doing what nature intended.

Sunday 10 November 2013

Goldfinches keep on coming

A bit of ringing in the garden over the weekend produced another 23 new Goldfinches and only 2 retraps. The number of Goldfinches ringed in the garden this autumn now stands at 282 which is the highest total by far and double the number ringed there last year. Juveniles have made up the bulk of the birds ringed with only 19 of the 282 new birds being adults. In addition 5 birds ringed last year have been retrapped. One of the juvenile Goldfinches caught today still hadn't completed its post juvenile moult and must have come from a very late brood.


Juvenile Goldfinch, still quite spotty around the head
In stark contrast to the Goldfinch totals the single House Sparrow caught was only the 4th ringed in the garden this year. How the tables have turned between these two species. When I started ringing in the 70s Goldfinches were not a garden bird and House Sparrows were very numerous. In fact there was a restriction on ringing House Sparrows at that time and you could only ring them if they were in moult and you completed a moult recording card. In those days you would see them on the corner of almost every roof but now you can travel large distances through a town without seeing any and there doesn't seem to be any halt in their decline.

male House Sparrow
Ringing totals for 9th/10th November
Goldfinch 23 (2)
Blue Tit 2 (1)
Greenfinch 2
Coal Tit 1
House Sparrow 1
Blackbird 1
Long-tailed Tit (2)
Great Tit (1)
Totals 30 (6)

Sunday 3 November 2013

03/11/13 Getting a grip

This afternoon the weather brightened up as forecast and I noticed a few Blackbirds starting to feed on the Rowan berries in the garden. Each bird didn't feed for very long and only took 3 or 4 berries at each visit. Some dropped a fair proportion of the berries they picked and it seemed to be a case of the bird letting them slip rather than actively discarding them.

Both adults and juveniles were involved so it is unlikely to be related to experience. The fruit are quite large and a Blackbird's beak is fairly long and narrow plus the gape isn't large like a Waxwing's so they can't just throw them into the back of their throat. They simply seem to lose control as they move them back along the beak towards the throat.

This bird loses this Rowan berry as can be seen in the next photo.

Full stretch

A bit of a mouthful
This is the first time my Rowan trees have kept their berries into November; they usually get stripped bare by early October. There is a bumper crop of Rowan berries this autumn and I am noticing heavily laden trees in places where I didn't know Rowan trees existed. It remains to be seen how long this glut will last and what birds it may attract.
Not much to report on the ringing front with heavy showers and or strong winds limiting ringing to a brief spell in the garden yesterday morning. That session produced another 13 new and 4 retrap Goldfinches along with new singles of Blue Tit, Greenfinch and Collared Dove. Two of the retrap Goldfinches were adults that had been ringed as juveniles last year and were duly photographed to add to my bank of photos of known age birds.