Willow Tit wanderings

I mentioned signs of juvenile dispersal in my last post having heard Nuthatches well away from their usual breeding haunts. Well it happened again today but this time it was a juvenile Willow Tit, that I first heard and then caught ,at one of my new ringing sites near Upholland. It was at least a couple of kilometres from the nearest suitable breeding habitat if not further. Now that may not seem far but it is still of interest, to me at least.

Note the wing panel formed by the broader warm buff fringes of the secondaries contrasting with the narrower warm buff fringes of the primaries.

This Willow Tit has a white area on the cutting edge of the upper mandible below the nostril. This is often regarded as a feature of Marsh Tit but is clearly present here.

Willow Tits often show a more extensive and untidy bib as can be seen in this bird.

Most juvenile birds don't disperse any distance until they have undergone their post juvenile moult but both Nuthatches and Willow Tits seem to disperse almost as soon as they become independent from their parents and often before post juvenile moult has even started. It must be important for them to move out of the natal area and find potential wintering/breeding habitat as soon as possible and is likely to be a factor in their survival and future breeding prospects. The Willow Tit I caught today certainly wasn't in suitable habitat to survive year round so its wanderings are far from over.

Willow Tits are also interesting because of their similarity to Marsh Tits, so much so that they were not recognised as a separate species until 1897 which is very recent in ornithological terms. In fact separation of Willow Tit and Marsh Tit remains a current topic for some although the rapid decline of both has removed that concern for many! Now I am not going to give you a complete 'how to' guide here but they do look different even in juvenile plumage and I still think the wing panel is still one of the best and most consistent features for birds in the hand. I have only caught two Marsh Tits compared with what must be hundreds of Willow Tits by now but both Marsh Tits stood out as being that bit different. The second one of my two was in the digital age and is shown below.

 

Juvenile Marsh Tit, Spurn Bird Observatory. Note the even appearance of the wing and the lack of a distinct wing panel compared to the Willow Tit above. This bird was only the 10th record for the observatory.

Other plumage criteria have recently been put forward to help with the separation of Willow Tit and Marsh Tit in the hand and both look like they may hold true, especially with regard to the colouration of the greater coverts (Broughton,R; BTO Ringing News).