Tuesday, February 9, 2010

Challenging IDs

There’s a really interesting letter in the current issue of British Birds (Vol. 103), concerning the identification of Willow Tit and Marsh Tit. To sum up, Dr JTR Sharrock and Barry Nightingale respond to a recent paper by Richard Broughton, and say that they feel he may have been too pessimistic. They add: “Positive field identification of these two species may be challenging, but it is – in our view – easier than that of, say, silent Common Chiffchaff and Willow Warbler”.

Now, I was thinking about separating the two when I was at Willington GP on Sunday, and I’d tend to agree with what they say. One thing that tends to get underplayed, in our experience, is the structure of the two birds – Willow Tits always look very bull-necked to us, and that seems to be a more reliable ID factor than any of the others (pale wing panel, shape of bib, glossy or non-glossy cap). The letter writers, to be fair, point out that the important thing is taking into account a whole combination of factors, and we'd agree.

But we'd like to know - would you find separating Willow and Marsh Tit easier than separating silent Chiffchaff and Willow Warbler, as they suggest? And are there any other match-ups that you find even harder?

7 comments:

Mr Uku said...

I recently saw my first Marsh/Willow Tit at Leighton Moss Last Friday. I know enough to be able to say it was one or the other, but not which one.

A local advised me that it was most likely a Marsh Tit because of the area, but he hadn't laid eyes on it.

I notice that the books always show Willow Tits as ever so slightly scruffier, as if the gel on their slicked back feathers had just started to dry. And that seems to ring true with my bird.
So, for the sake of making my own ID, and having no other evidence, I shall add, Willow Tit, to my list.

Crafty Green Poet said...

In Edinburgh we don't have the willow vs marsh tit issue as we don't have either of them! I do find silent chiffchaff vs willow warbler impossible to id.

BW said...

What puzzles me slightly is why one or the other species is present or absent in a particular area. Here around our Peterborough offices, Marsh Tit is pretty much the only one present, but where I live near Leicester, Willow Tits are easier to find.

Robin Edwards said...

I'm confident that given the opportunities birders had in years past to compare Marsh & Willow Tits in the field then folk would learn key differences just like they do for other species such as the Chiffchaff & Willow Warbler as mentioned. Living in Bedfordshire is not likely to afford birders such opportunities these days unless both species see a significant improvement in their numbers. From my experiance when birding in other areas of the country it is either one species or the other that I see and not both together and not in significant numbers. From what I've learnt, seen well I believe the upper bill of the Marsh to have a pale patch that I haven't seen on Willow.

BW said...

Good point, Robin. One of the things that would make Chiffchaff and Willow Warbler easier to separate (assuming they stay silent) is the fact you stand a reasonable chance of seeing both in fairly close proximity. As you say, it seems to be one or the other with Marsh and Willow Tit.

PMella said...

Redpolls, "Commic" terns, and juvenile gulls are also big contenders for ID challenges to rival willow/marsh and willow/chiff...

And how about a non-visual ID challenge - the difference between blackcap and garden warbler song?

BW said...

I like that one, Pete. Can be very tricky.

Commic terns are often a struggle just because they're so active, redpolls because you so rarely get good unobstructed views, and juvenile gulls...don't go there!