After 7 months of joint work and adventure, Elena is leaving the MigraTagis project. Her first task, totally accomplished, was to carry regular counts of waders at some estuarine foraging areas. Afterwards, she switched the muddy field and the telescope by a laboratory, a pair of gloves and a pipette. She was the first geneticist of our team, specialized in molecular methods of bird-sexing: at first learning and then teaching other team-members! Thanks for your joy and friendship, and….see you around!!!
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...
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!
Last week David submitted his thesis entitled “The use of intertidal areas by foraging waders: constraints on the exploitation of food resources”. The thesis is currently being analysed by the Scientific Council and the viva will take place within a few months. The thesis is composed of 6 nice papers, some of them already out. Congratulations David, very well done!
Two more sessions at Samouco and Pancas, and another 90 dunlins marked flying around. Mist nets and ah... “traps” were used with great success. Thanks to the “elite” teams, great job, great mood, and of course great work!
After some relatively small catches (10-15 per session) at Brito Salinas, we made a FANTASTIC catch, well above our best expectations: more than 100 birds!! We released a few birds straight away from the net, because the team was relatively small (previous sessions undermined our optimism and we didn’t want to bother too many people…). Anyway, the team was superb, always very focused and swift. Some (most welcomed) reinforcements arrived a little later and we ended up by processing 72 birds. One of them had a Spanish ring, it will be interesting to know its story.
This great catch boosted our moral, and provided excellent training to everyone. Excellent discipline, hard work, but also very good humour (especially as the boxes were getting empty!). There are 185 dunlins now tagged in Tagus estuary (a lot of them marked yellow (picric acid) on the breast), so again, any sighting is most welcomed! Anyone in Siberia??
We are still accepting volunteers to learn with and help in our catches!!
