Nick Upton's picture

Willow tit with beakful of green caterpillars.

Observed: 2nd June 2013 By: Nick UptonNick Upton’s reputation in BirdsNick Upton’s reputation in Birds
Willow tit (Poecile montanus) with beakfull of green caterpillars.
Willow tit with caterpillars
tit tail
tittail2
Marsh tit (Poecile palustris) bi-coloured cheek
Willow/marsh tit beak
Description:

I'm pretty sure this is a Willow rather than a Marsh tit based on the large scruffy bib, extensive white cheeks, not very glossy cap and hint of a pale panel on the wings.... but would appreciate confirmation or correction. This one was feeding its mate in early June, perhaps prior to mating, rather than visiting a nest as far as I could make out, but I didn't hang around for long in case I upset them. They were foraging among hawthorn bushes and finding more caterpillars very fast. If anyone can ID those, gold stars should be awarded!

Identifications
Species interactions

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Comments

jerebarker's picture

Not sure

Could well be Willow, but wouldn't like to commit on those photos. The pale panel in the wing isn't exactly eyecatching, though it's not always easy to pick up anyway. The thing that bothers me is the relative length of the tail-feathers just visible in the second photo.

Willow should have the outermost tail feathers much shorter than the others, then a visible gradation in tail feather length to the centre (see e.g. http://www.ispot.org.uk/node/311256?nav=related), whilst Marsh should have the outer pair shorter (usually less so than Willow) and then a big gap with the rest of the feathers rather equal in length - see http://www.ispot.org.uk/node/311250?nav=users_observations if you wish!

The photo appears to show a Marsh Tit-pattern, though the resolution's not brilliant. Not often you get a photo which shows this at all in the field though!

Edit: breeding's pretty much done & dusted for the tits now; they're single-brooded, so birds doing this are feeding young in or out of the nest.

Nick Upton's picture

Tit tails

Many thanks for these comments. I didn't know of the tail feather ID trick... and have added crops from two other images where the focus was quite sharp on the tail.

I realise photos are rarely definitive and this link http://www.britishbirds.co.uk/wp-content/uploads/2010/10/Willow-Marsh-Ti... spells out just how much overlap there is in all the commonly used field characters. It also says the tail feathers only help for birds in the hand, but just maybe these pics are clear enough to say which species this may be??

I realise I need to tune in on the calls / songs to be really sure..

The photos were taken around 3 weeks ago on a rare warm, belated spring day - and I saw one bird feeding its mate, but they may have had a nest nearby.

Nick Upton, naturalist and photographer.

jerebarker's picture

Tails

Nice. Personally I think those photos tend more towards Marsh than Willow - nice to get such a good couple of images in the field, by the way - but it is, ideally, an in-the-hand character, yes. The advantage of ringing and doing studying the two species locally! They aren't easy even in the hand, sometimes.

There is certainly overlap in the bib extent and appearance, and I think the character varies somewhat with season and feather wear too. Likewise, the appearance of a pale wing-panel is somewhat dependent on feather wear too. I don't like the glossy vs matt cap personally, as it's age- and light-dependent, and structural characters are much easier with prior experience. The pale spot at the base of the upper mandible is also a good Marsh Tit character, as is the colour of the cheeks - tends to be bicoloured in Marsh and whitish all over in Willow.

I think the song & call would be well worth getting to grips with, as they are the easiest method by far of discriminating the two species. Being very sedentary species, they should be just where you left them, so if you've got the chance, have a good listen. At the moment both species should be a little more noisy than they have been for the past month.

Richard Broughton's been studying both UK Poecile species for a good long while and the paper you link to is an excellent resource... well worth absorbing it!

J

Nick Upton's picture

Marsh/Willow conundrum

Many thanks for your expert input. I may well return to take more careful note of the calls. I was concentrating so hard on framing/ focusing that they didn't register enough. I was really at the site to photograph butterflies, but had a big lens with me so put it on when I encountered this pair.

I've now added crops that show what may be a bi-coloured cheek with a white front panel grading to much warmer buff, which is closer to these images of a marsh: http://www.birdforum.net/attachment.php?attachmentid=126682&d=1203341738 than a willow http://www.birdforum.net/attachment.php?attachmentid=126681&d=1203341729 within this post http://www.birdforum.net/showthread.php?t=107725

I have no convincing images of the beak spot as the caterpillars mask it in all but one poorly focused image. I attach a crop anyway in case it helps, but think it could be interpreted either way as the light spots are reflective highlights.

If these extra shots make it more likely a Marsh, please feel free to update the ID. If they don't I guess it's unconfirmed either way until I've checked the calls!

Nick Upton, naturalist and photographer.