Autumn Update

Posted on Nov 9, 2014

It’s been almost 3 months since I left Latvia, having completing field season #2. After what seemed like a good start to the breeding season, a spell of poor weather resulted in massive chick mortality. This resulted in only 6 successful Roller nests (out of 19 known attempts) and 15 fledglings (out of 73 known eggs). So, quite tragic, as well as reducing the sample size for several of my planned analyses.

Cutie pie

Cutie pie

Here’s a bit of what I’ve been up to since then:

Stable Isotopes

A very dull three weeks were spent in the lab preparing insect and feather samples (370 in total) for carbon and nitrogen stable isotope analysis. Adult primary feather isotope signatures will in theory tell us something about what they get up to in Africa, and we’re hoping to understand more about chick diet by comparing the isotope signatures of their feathers to those of insects sampled from different habitats.

French cicadas, ready to be dismembered, freeze dried, ground and weighed

French cicadas, ready to be dismembered, freeze dried, ground and weighed

Freeze drier (for insects)

Freeze drier (for insects)

Balance station

Weighing station

The final results came through last week, so I’ve now got a bunch of stats to do before I can get too excited. But the good news is that the insect samples definitely vary in their C/N signatures, so it should be possible to estimate the proportion of different types of insect that were metabolised by each chick to build the keratin in each feather. Watch this space

Geolocators

This field season we recovered a 2012 geolocator in Latvia, as well as three 2013 tags from France.

One geolocator - deployed in 2012, recovered 2 years later

One geolocator – deployed in Latvia in 2012, recovered 2 years later

Colleagues in Cyprus and Portugal also got one and two tags back respectively, and we have access to data from two tags recovered from Rollers in Montenegro in 2011. The plan is to combine these data, along with some already published data (here and here and here) into a continent-wide analysis of migratory connectivity. Migratory connectivity describes how migrants from different breeding populations mix during the non-breeding season, and has really important consequences for population dynamics and conservation. This has required many hours spent at the computer navigating the minefield of geolocation by light. I’ve also been having fun making some pretty figures. Assuming all goes smoothly (a dangerous assumption, in my experience), we plan to submit this paper by Christmas.

Genetics

We recently took on a Master’s student who will be extracting feather DNA from Rollers across Europe. The plan is to sex all individuals, and then go on to do some population genetics. Our aim is to figure out the relationships between Rollers from different populations, in addition to comparing the genetic variation within each population. More from Katherine later, I hope.