On 10th August we wrote: A 1cy female Collared Flycatcher was trapped and ringed at the Warren this morning. Identified by the combination of the following;
10 August 2020
- Extensive white wing flash, extending to a small spot on P4 and around 1.5mm beyond the primary coverts at its longest point.
- Wing measurement of 83.5mm (Pied Flycatchers to a max 82mm (per Svensson))
- Extensive white along outer web of T4 (most Pied Flys have a black T4 and only a few show a small amount)
- Nice, broad, really white tips to greater coverts
- Did not appear to show a ghosting of a rump or collar in the field, (some photos show a slight hint of a greyish rump area), a slight greyish tint to upper tail coverts
- Mantle shade same as Pied Flycatcher in direct comparison, no obvious greyish tones to it
- P2 = 4/5
- No calls were heard
A few feathers were dropped during the ringing process and will be sent for DNA testing to hopefully prove our thoughts on this subtle identification of a tricky species/age group.
It continued to show on and off from late morning, before it disappeared in the afternoon before re-appearing in the evening.
A few feathers were lost during the ringing process and were sent to Martin Collinson and Thom Shannon at Aberdeen University to do a full DNA test.
The resutls are back, it's Pied Flycatcher! Not even a hybrid! Thom did both mitochnodrial (DNA from its mother) and nuclear (DNA from its father) DNA test and showed that both this birds parents were Pied Flycatchers! Second generation hybrids are thought to be extremely rare/non-existent as it appears most first generation hybrids are infertile.
So, even birds like this one that seemingly show features consitent with Collared can still fall within range of extreme Pied. Does this mean the bar moves even higher for identification of autumn 1cy Collared Flycatchers? We'll certainly be even more cautious than we thought we were being with this bird, before being so confident about the next one!
As Lars Svensson quotes at the start of his ringing guide "NEVER UNDERESTIMATE THE EXTENT OF INDIVIDUAL VARIATION!" As the late and great Martin Garner always used to say "ALWAYS LEARNING!"
