Marsh-Willow Tit

Check out those mandibles!

A Spot of  Geometry

You may recall my mentioning a marsh tit back on my ‘patch’. I wondered whether I was witnessing ‘connectivity in action’, as much of it is hedgerow, and the nearest substantial woodland is some distance away. But since then, I’ve got rather used to seeing this compact, lively, likable little bird on my morning walks and I’ve come to think that he (or she) looks rather at home.

I’d read in a paper this summer that few marsh tits breed in woods smaller than 10ha and, glancing at a map of my patch, the nearest wood that large is some 2km ‘down-hedge’. But that is to assume that a 25-metre wide strip of small trees and woody shrubs like blackthorn is not seen as ‘woodland’ to a marsh tit, or indeed the 40-metre wide stretch just to the west, lined with mature trees. Take this into account and in effect the site of my morning walks lies on the edge of a near unbroken 8ha wood, with 6ha more close to the western end. A 14ha deciduous wood lies almost 2km to the east, and seems a better candidate for a good size marsh tit colony — but I’ve never seen one in the narrower hedgerow on the way there. I would imagine that this little bird is indeed a pioneer, establishing itself on the fringes of what would be good habitat for the winter but finding good food, away from a colony to the west or east.

Alternatively, I could be stumbling across individuals of a colony which persists in a wood and hedgerow complex of sub-optimal size but nonetheless provides all of the basic needs of a marsh tit. This morning I got quite a clear look at a one bird taking a brief break from its breakfast. The rear of its cheek was buff-coloured in a rather untidy way, its bib small and very neat, black cap likewise tidy and narrow on the back of its neck. There was the trace of a pale line along the secondaries, and I could just make out a pale spot on its upper mandible — of which more later. I intend, though it’s a daunting task, that I might be able to identify this individual again. Its presence on my patch is another puzzle to add to my list of things I do not know and may never have time to find out.

Birds of a Feather

Of course, I could hardly mention marsh tits without also mentioning willow tits. I seem to have a penchant of late for closely related birds. Alas for willow tits the situation in Britain is fairly desperate: a 76% decline since 1995. Their subsequent addition to the list of rare birds requiring special monitoring was fairly well publicised this summer, and highlights quite how difficult to find they are becoming in many parts of the country. Willow tits prefer newer growth and damp woodlands near to water features, when compared to marsh tits which will go more for mature, established wood — of course, in nature things are never simple and there is some overlap in where you will find them.

In the marvellous ‘Netherton Bottom’ in North Hampshire the overlap is quite evident as here you can find all six species of British tit (discounting what should really be called Bearded Reedlings). It’s the perfect place to try for the six tit challenge. On a visit a few weeks back we heard a calling willow tit only 15 minutes into our walk and located the bird quite easily. Last Friday we spent twice as long in the valley for less return. No willow tits were in evidence at all.

Unsurprisingly, their possible appearances overlap too, and the latest position is that the only surefire way of separating the two on sight is the paler edges of a marsh tit’s mandibles. Try getting a good look at that in the field — not impossible, and since I read the paper I’ve noticed the pale mandible on a handful of marsh tits, including my adopted patch friend, for example. Or at least, I imagine I have. You’ll often hear pale panels on the wings of willow tits mentioned too, which I’ve noted on any that I’ve seen well — but it is not foolproof. Note what I said about my marsh tit’s secondaries.

One from Another

Assuming you are out in the woods and you come across a little brown buff tit with a black cap and bib, how then do you tell them apart? The best way is, of course, by song or call. It’s no use my telling you what the song sounds like at this time of year, as you probably won’t be hearing it until February at least. So here’s my patented HatBirder method for learning the calls:
See? Really quite simple. Marsh tits sound like a little sneezing bird — ‘Pitchoo! Pitchoo!’ The first syllable is higher, but the emphasis is generally on the second. Willow tits often say exactly what the Collins guide says they do: “zi-zi tah tah tah”. The tone of voice is buzzier than marsh tits — in fact, some of the extended calls sound a fair bit like squeaky toys. Hear for yourself, with songs and video too over on the BTO website:

Both are brilliant. Wait, all are brilliant!

So once again I cheat: two species for the price of one, our resident Poeciles. But it’s hardly cheating, since the actual experience of watching marsh and willow tits is fairly similar. Both are charming, cheeky birds of the woods — anchor birds in arboreal habitats which bring them to life and complete any woodland ecosystem experience. I urge you to try learning to separate them; not only is it satisfying, the red list status of both species makes it pretty useful too. And if you think ours are difficult, try their North American relatives the black-capped and Carolina chickadees. One or both of which I hope to see in the next two weeks: I’ll be unhelpfully close to where their ranges overlap. Some Poecile-related Christmas fun to look forward to!

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