Wednesday, September 9, 2015

Mid-Week Blues

The weatherman offered a couple of bright hours before the wind would pick up to make bird ringing impossible. The forecast for weekend looked more dire still, so it was now or never. I decided to head up to Oakenclough for a spot of solo ringing. 

There was full cloud throughout together with a cool breeze as the anticipated bright intervals failed to materialise. I ended up with a disappointing 10 birds - 4 Goldfinch, 2 Goldcrest, 2 Blue Tit, plus one each of Coal Tit and Blackcap. 

Good numbers of Siskins, 25+, were in evidence again but I failed to catch a single one. Even the normally exuberant Lesser Redpolls stayed out of sight with just a couple of flyovers to note. The light was so bad this morning I had to shoot birds in the hand at a far from ideal ISO1600. 

The Blackcap is a first year female. 

Blackcap

The Goldfinch below is a first year undergoing moult transition to a first year female. It is in body moult, hence the feather debris, has replaced the two central tail feathers and is in the process of re-growing the two outermost tail feathers. 

Goldfinch

Goldfinch tail

A completely juvenile Goldfinch cannot be sexed until there is some colour around the head. By September a juvenile at this stage could be from a third brood and it is noticeable this week how many Goldfinches are still feeding recently fledged youngsters. The middle picture below was taken on Sunday 6th September. 

Goldfinch

Goldfinches
 
Goldcrest

There didn’t appear to be many Chaffinches around this morning with probably less than 15 seen/heard. The only one caught had a severe case of viral infection to its legs, one leg far worse than the other. The Chaffinch was an adult male and apart from the leg infection seemed in overall good condition, having recently undergone a full moult. It goes without saying I hope that birds displaying any hint of this condition are not  given a ring on either leg.

 Fringilla papillomavirus

Ringers who catch good numbers of Chaffinches see this disease regularly. It is known as Fringilla papillomavirus (FPV). 

The species susceptible to this are Chaffinches and, to a lesser extent, Bramblings. In a large survey of birds captured for ringing in the Netherlands, papillomas were found on 330 (1.3%) of some 25,000 Chaffinches examined and both sexes were affected. However, cases usually occur in clusters and quite high proportions of local populations may be affected in outbreaks. The fact that cases occur in clusters suggests that the presence of affected birds presents a risk to others that are susceptible. The mode of transmission is not known but it seems likely that the virus may be spread via surfaces the birds stand or perch upon.

Even birds with large papillomas often appear to behave normally so, in some cases, the growths may be little more than an inconvenience and relatively minor irritation. However, lameness is sometimes observed.

My own observations over the years suggest that the disease is more prevalent where Chaffinches mix with chickens and wildfowl in both farm and smallholding situations, perhaps even in gamebird rearing situations where feed is either spread upon the ground or spilled via feeding devices. 

The morning’s birding was as equally quiet as the ringing - Sparrowhawk, Nuthatch, Grey Wagtail and Great-spotted Woodpecker of note

6 comments:

Sallie (FullTime-Life) said...

It amazes me how sweetly the birds sit letting you photograph them in hand. That is sad about the disease. I hope they can recover .

Linda said...

How sad to see this disease, Phil. Your bird photos are gorgeous, and most welcome, as always!

eileeninmd said...

Hello Phil, it is sad to hear these sweet birds have this disease. And it is scary that the virus can be spread via the surfaces. The Goldfinches are such pretty birds. Great post.

David Gascoigne said...

Wow, that looks awful. But if it does not seem to affect them in other ways it's probably not so bad for them to cope with and I suspect they don't worry about the aesthetics.

Stuart Price said...

Every winter I see quite a few Black Necked Grebes with some weird growths around the base of the bill/eye. It doesn't seem to stop them feeding at least.

Chaffinches should stop pilfering liverstock feed then!

Margaret Adamson said...

It is amazing how the birds can still carry on with that disease. Love the shot of the Goldfinch tail

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