|View over the breeding area from the helicopter on June 15.|
After one month of fieldwork at Lake Latnjajaure the field season is now over for my part. The aim has been to catch Common Ringed Plover to retrieve light level geolocators and deploy new ones. Earlier this spring I was also catching plovers at Ottenby on Öland, which I wrote about in a previous post. The purpose for this study is to gain more knowledge about different migration strategies between populations breeding and wintering at different latitudes.
When I left Ottenby in the beginning of June spring had passed on to summer, so it was a treat to experiencing spring a second time up north. This was my third visit to Latnjajaure since 2014 and as usual the work started off in a wintery landscape. Most of the breeding ground for the Common Ringed Plovers was covered by snow. However, from the helicopter, on the way towards the site, it was easy to spot where the nests will be laid. The only bare spots in mid June when the birds just have arrived or only ben present for a week are located on end-moraines. These are subjected to heavy wind erosion and it is there most nests will be laid.
|One of the Ringed Plovers with Lake Latnjajaure in the background.|
It took only a short walk around the field hut to locate two of seven birds that were equipped with geolocators last year. After a couple of more days four had been spotted and after an additional week the first active nest were found. That particular nest or rather “scrape” (Ringed Plovers digs a little hole in the ground which they only “decorate” with pebbles) had been used three consecutive years by the same male. In addition, the first two years he was breeding with the same female! This year they had divorced, but the female were still in the area. More precisely 300 meters away, in a new nest with a new male. During the following days three more nest were found. In total 4 out of 7 individuals with geolocators returned this year, which is a 57 % return rate. This is as high as the estimated return rate for birds without loggers.
On the 29th of June Juliana Dänhardt joined me for the trapping. The first three birds were rather easy to catch, but one male repeatedly refused to walk into the walk-in-trap. After trying several times a day for a week we were close to give up. But late in the evening the day before heading home we succeeded. Actually, it was the fastest catch I ever had only taking three minutes after placing out the trap.
Now I am looking forward to start analysing the 4 loggers from Lake Latnjajaure and the in total 8 from Ottenby (where two might include up two years of data). This sums up to a successful field season and gives great hopes for next year!