First Paper Submitted!

Posted on Apr 14, 2015

At the end of January it was a relief to finally submit the first paper of my PhD – “A pan-European, multi-population assessment of migratory connectivity in a near-threatened migrant bird“. As the title suggests, this paper is about migration – probably the only chapter of my thesis which will focus on goings-on away from the breeding grounds.

In addition to the 4 & 6 geolocators we got back from Latvia and France, I incorporated new tracking data from Cyprus (hat-tip to Phil), Montenegro & Austria (from Michael Tiefenbach) and Portugal (from Inês Catry), as well as data from the three existing studies of Roller migration (from France, Portugal and Spain) and the only African ring recovery (Bulgaria to Tanzania).  This forms the largest-scale study of Roller migration to date (and is a pretty good effort compared to most tracking studies of small-ish birds, which often use data from just a few individuals from a single site). 

Distribution of sites for which we have tracking data (the brown point is the Bulgarian ring recovery; 6 of the green points in Spain are satellite tags; the rest are solar geolocators)

Distribution of sites for which we have tracking data (the brown point is the Bulgarian ring recovery; 6 of the green points in Spain are satellite tags; the rest are solar geolocators). The shaded green area is the breeding distribution of the European Roller (from BirdLife).

I probably shouldn’t reveal too much until the paper is out (still no news from the reviewers..), but all of ‘our’ Rollers wintered in southern Africa, with western breeders tending to winter in the west and vice versa (parallel migration). We also found evidence of loop migration (i.e. differing routes in spring and autumn), particularly in our Latvian birds which made a detour to the Horn of Africa and Arabian Peninsula in the spring (in contrast to a fairly direct, southerly route in autumn). Another interesting pattern was the leap-frog migration which seems to occur in the eastern flyway; the Latvian birds breed to the north and winter to the south, whereas the Cypriot bird (n = 1, ahwell!) bred to the south and wintered to the north.

The cool thing about having data from multiple populations across the European range is that we can start looking at migratory connectivity. This describes the mixing of individuals from different breeding populations over winter, and can be described as strong (when different breeding population segregate completely over winter), weak (when different breeding populations mix up over winter) or (more likely) somewhere in the middle of this spectrum. The strength of migratory connectivity has important consequences for things like the response of populations to habitat loss, but for most species we have basically no idea where they fall along this spectrum.

I look forward to sharing more of the specifics once the peer-review process has worked its magic.

A new geolocator deployed

A new geolocator deployed

It’s been a pleasure to present this work at some recent conferences, including UEA’s CEEC Rebellion and the #BOU2015 conference, held in Leicester a couple of weeks ago (where I attempted to tie in the geolocator stuff with some feather isotope stuff). Feedback was good, both on twitter and in real life. The event was really well covered on Twitter actually, so if you missed it and can’t wait for the official Proceedings, then check out this storify put together by Tom Evans. If you scroll down for about 10 minutes, then you get to me (Thursday, Session 2, Talk 2). And here’s me in action – cheers Dr. José!