...and perfecting old skills!

As our previous post points out, we trying to catch-up with the high-tech world of genetic, but meanwhile we still struggle with the more familiar low-tech methods of seeing what kind and amount of food is available for our waders.

So, this is not gold-prospecting but rather worm-prospecting, which is basically the same technique and amount of effort, with a rather different profit… Thanks to all that helped in this hard work, especially because it took palce during the hottest days (32ºC) of this strange spring. The colour of the water looks wonderful for a refreshing bath afterwards...

Developing new skills

During the last few months, Elena Sierra, our Spanish team member from Madrid, has been working hard to learn a molecular genetic method to determine the sex of dunlins caught and sampled during the last winter and spring. For each blood sample, DNA is extracted from the sex chromosomes and amplified by PCR, using the primers P2 and P8. The PCR products are then separated by electrophoresis in agarose gel, allowing to distinguish one or two bands, which represents a male or a female, respectively (see photo below).

Sexing dunlins is extremely helpful to increase the potential for assignment of different subspecies among the birds that use the Tagus estuary both during winter and migratory periods. Althought birds from distinct subspecies differ in morphometric characters (such as culmen length), there is still substantial overlap. Given that dunlins show sexual dimorphism, biometric data analyses are greatly improved by using sexed birds.

We are extremely grateful to Mónica Silva for her tireless help during all this learning period!