Birds in Focus - Marsh Tit and Willow Tit

Willow Tit (RSPB)

Marsh Tit (RSPB)

The Marsh Tit and Willow Tit are an example of a 'twin species' and are a pair of birds that are very difficult to tell apart.  Traditionally the following characteristics have been used:

1. Voice or call
2. Distribution - i.e. where it's found
3. Head colour and appearance - Marsh Tit has a glossy black cap, whereas the Willow Tit's is dull black
4. Wing panel colour - Willow Tit has a pale patch on the inner wing which Marsh Tit lacks

The bird's call is a surefire way of identifying each bird, but what if it's not heard?  There is increasing evidence to show that the other three methods are not always as conclusive as first believed because both birds can at times display similar features.

Recent suggestions for telling the two birds apart are:

1. A 'smeary' white mark at the base of the Marsh Tit's upper mandible which is missing on the Willow Tit
2. Grey-brown hues on at the neck-sides on the Marsh Tit compares to warm buff hues on the Willow Tit

The best place to see these birds in North West England are:

• Marsh Tit - Leighton Moss RSPB
• Willow Tit - Pennington Flash Country Park or Astley Moss

Whichever method is correct, the two birds obviously give even the experts plenty to discuss and so for many birders the chosen method will still be voice first, followed quickly by distribution.

Here's a BTO identificartion video: