WILLOW AND MARSH TITS - OUR SPECIAL BIRD SURVEY FOR THIS YEAR.

The subject of our survey for 2010 is Willow and Marsh Tits.

Willow Tit (left) and Marsh Tit.
Photos: Peter Walkden (left) and John Robinson

Details of any sightings during 2010 will be welcome, please report: number of birds seen, date seen, location (with map reference if possible), and details of any activity such as singing, feeding, nesting, carrying food, etc. and also add your name and address.

Note: The last acceptable Somerset record of Willow Tit was in 2003 but the species still survives at a number of North Devon sites. As they are difficult to tell apart (except by call), see notes below to help:

Identification is far from easy and it can take a great deal of practice to confidently separate the two species. The key thing to remember is that relying on one or two plumage features could result in an incorrect identification. Instead, more emphasis should be placed on the birds overall structure and particularly the head and neck. Unlike the Marsh Tit, Willow Tits excavate their own nest hole which undoubtedly explains why they have a thicker neck. The overall body shape often has an ‘egg like’ appearance with a large rounded head while their plumage can often appear scruffier due to their looser, fluffy feathering whereas Marsh Tits often appear sleek and ‘well groomed’.

Willow Tits have a long, dull black cap that extends well back on to the mantle, noticeably further than on Marsh, but this can vary greatly with posture. Furthermore the shape of the head and cap also provide Willow Tits with larger, more extensively white cheeks, whereas those of Marsh Tits often have a two-toned effect being buffer at the rear but some individuals can appear as uniformly white as Willow Tit. Another feature that is often quoted in field guides is the glossy black cap of Marsh Tit, but little emphasis should be placed on this as it is lacking in juveniles, while in poor light conditions both species will appear to have dull caps. The size of the black bib is another variable feature and those individuals that have extensive bibs with a suggestion of black peppering flaring out at the bottom are more likely to be Willow while those with smaller clear cut bibs are more likely to be Marsh but there is overlap between the two species.

The upperparts of both species are a uniform brown, being slightly darker on the wings. Willow Tits often show pale edges to the secondaries producing a pale wing panel but birds in worn plumage during summer may lack this feature. To add to the confusion, fresh plumaged Marsh Tits can show a suggestion of a pale wing panel.

Marsh Tits often have a pale mark at the base of the bill and this can extend along the cutting edge while Willow Tits generally lack this feature. Unless the views are extremely good this feature will probably be of limited use in the field, but apparently it can be very reliable for in-hand examination.

However, all of these visual characteristics are not wholly reliable in the field especially if the views are less than satisfactory. Fortunately, as with all members of the tit family both species are often very vocal. Their calls are quite different and once learnt they should not only allow for an accurate identification but also for locating individuals in the first place.

The most frequently heard call of the Willow Tit is a harsh drawn-out nasal ‘chay-chay-chay’ or ‘ti tis chay-chay-chay’, whereas Marsh Tit gives out an explosive ‘pitchou’ often followed by ‘chu-chu-chu’. Their songs are equally distinctive with Willow Tit giving a slow and measured Wood Warbler like ‘tsui tsui tsui tsui’ while Marsh Tit has a quicker, more repetitive ‘swe swe swe swe swe swe swe’ call.

See “Your Records” section re sending records by email.