Sunday 22 January 2023

Marsh Tit or Willow Tit, Willow Tit or Marsh Tit - The Hazards of ID

 Bird identification in the UK is, on the whole, pretty simple. Many of the species can be identified readily enough by sight or sound, behavior, and location. One species however has always plagued me. Marsh Tits and Willow Tits. These two species are morphologically indistinguishable at distance and up close still very difficult. Their songs are diagnostic but I have found my ear is not very well attuned at identifying bird songs. 

In the records of my patch, I have a record of a Willow Tit recorded in 2003 and 2004. Back then I was less experienced and although I make a vow of accepting my early sightings I suspect that my diagnostic feature for this species was the fact that it was seen in Willow and Alder Carr rather than any morphological details.

In 2007, 2011, and 2012 I have records of a Marsh Tit, but this time I had photographs because it regularly visited a feeding station.



In these pictures, I identified the Tit as a Marsh Tut based on the glossy cap. But let's break this down a little. The bib is fairly large and neat, and the cap seems glossy, the tail seems flat, not rounded and there is evidence of a pale spot on the upper mandible but this could just be the light reflecting.

So now we come to this week's birds, several of these tits have been seen recently and so I set up a camera on a feeding station and got the following shot, which is a still from a video clip.


From the grainy image we can again see a square tail and what appears to be a white spot on the upper mandible of the beak... Marsh Tit? Maybe but then I heard one calling and felt it was reminiscent of a Willow Tit.

So, after much research including The Helm Guide to Bird Identification and the very interesting Bird ID from Nord University website, I went back down the mill to try and get a better photo and hear it call. Both happened. Below are close-ups of the bird I recorded today.




These images show a flat-ended tail, a large white cheek, and a cap that is sort of glossy, there is also a very small suggestion of a white mark on the upper mandible. The black mark beneath the right is an individual trait not indicative of the species. It actually proves that there is a pair as the video camera bird lacked this mark.

This individual however flitted away from the feeder and sat in a hazel tree and called. I was unable to record it on my phone but noted in my field notes that it sounded like : zuuu Chee Chee.

The song is supposed to be diagnostic in these species and so I used the excellent xeno-canto website to see what it was. Marsh Tits can be heard at and Willow Tits at. From this, it sounded definitely like a Willow Tit.

So let's look at all the criteria in summary:

Call - Sounds more like Willow Tit than Marsh

Cap - Seems glossy in some shots Marsh Tit), could be either. But stretches down the nape more like a Willow Tit

Neck -  fat neck diagnostic of Willow Tit

Cheeks - Pure white cheeks with clean break into greys more like a Willow Tit

Bib - Neat bib like a Marsh Tit but broader like a Willow Tit

Tail - Flat ended with no degree of rounding like Marsh Tit

Back/Wings - Greyer than brown like the Willow Tit

Habitat - Willow/Alder Carr preferred by Willow Tit although both species overlap.

Given that there are many overlaps in the morphology and habitat the call is perhaps the most important and so I have to conclude that the individual I saw today and was on my trail cam was a Willow Tit.

But what about the ones I saw in 2011/2012, should I revise my identification? Without the call, there is no definitive answer. Morphologically it has a flat tail and a glossy head suggesting a Marsh Tit but my gut says they will be Willow Tit given the latest information. For now, I will respect past me's ID but in any research report I will probably list them as Poecile sp. to indicate that I cannot reliably differentiate the two species. 


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