Spotlight Species: Azure Tit

It must have been devastating for hundreds of Swedish birdwatchers. All of them happy and excited to have seen two Azure Tits in their home country.

But then, the first few doubts, presumably by some spoilsport eBird reviewers who either did not manage to see the birds or had already seen them before. Wasn’t the plumage a bit off, showing some characteristics of Blue Tits?

So, were these really Azure Tits, countable in hundreds of Swedish life lists, or just some mongrels, that is, hybrids, and thus pretty much worthless to our dear listers? How to find out?

The optimists among the birdwatchers – believing in their luck – had a solution. Crowdfunding! Do DNA tests of the two birds in question and compare those with museum species of Blue Tits, Azure Tits, and known hybrids.

And indeed – I gave it away in the very first sentence – the two birds turned out to be hybrids. To be specific, first-generation hybrids between the two species – hybrids that even have their own name, Pleske’s Tits.

This is how I figured it happened, based on a research paper titled “A crowd-sourced genomic project to assess hybrid content in a rare avian vagrant” – kind of the dumbed-down movie version with added emotional content to increase viewership.

Now, if this were another bird, I probably would not spend 5 or 6 paragraphs just to tell this story. But:

1. I have some very nice photos of the species, so I needed enough text to justify showing them.

2. There seem to be pretty much no other scientific papers covering the species, requiring me to use the one existing one in a very frugal manner.

What else? I saw the bird in the reeds next to the frozen river running through Hailar, Inner Mongolia in December – behaving quite a bit like a Reed Parrotbill. To quote from Cornell on their feeding habits:

“Very active, with fairly quick or rapid movements, climbs straight stems and reeds easily”

“Gleans food items from substrate, and breaks open stems of plants to reach hibernating larvae”.

By the way, the paper mentioned above ends up arguing that all Azure Tits observed in Europe outside its natural distribution may be hybrids to some extent. So, maybe the Swedish birders need to come to Inner Mongolia to see the species like I had to.