A night at the radar

It’s the 9:th of September and my fieldworks starts with me taking the bus down to Falsterbo bird observatory’s field station. There I fill up my coffee thermos and then bike out to our ornithological radar, situated outside Skanör. It’s a tracking radar that follows individual birds as they pass the peninsula, giving exact position, speed and altitude of the birds.

20:30 I arrive at the radar, it is clear weather and not much wind. I turn the radar and the computer on and wait for the radar to warm up. It takes some minutes for the radar to warm up and be able to emit the radio waves. They are emitted from the large disk antenna on top of the radar, bounce of solid objects and are then registered by the radar it returns. This gives us a means to follow free flying birds without having to handle or interrupt their behavior in any way.

20:40 I track the first bird of the night. I cannot see the birds, but I see the eco on the radar and the computer plots the track and shows me the speed and altitude of the bird in real time. This first bird is flying strait against southeast at a ground speed of about 9 m/s and at a altitude of 900 meters.

21:30 There are a lot of birds tonight, not surprising since there have been several days of bad weather before tonight. Tonight it is perfect migration weather, clear sky and very low wind. Which is lucky, because tonight is also Canmoves moon watching event. This also means that the radar in Lund is being operated tonight as well, and from the reports they seem to also be having a good night.

22:30 I take a wind measurement by releasing a helium filled balloon with some aluminum foil attached and then tracking it with the radar by the reflections of the aluminum foil as it drifts with the wind. This gives us very precise wind measurements from all the altitudes the birds are flying at. I track it with the automatic tracking until it reaches 2000 meters of altitude, which takes about 20 minutes and gives me some time for a coffee break.

01:00 There is really a lot of birds in the air tonight. In the beginning of the night most of them where heading towards south-southeast, now I see some return migration as well.

01:30 Time for another wind measurement. Some clouds have started to gather, but the wind is still quite low and strait towards east. More coffee!

03:00 The birds have started to thin out, even though there are still quite a lot in the air. I pack up for the night, happy to have tracked about 120 birds during the night, most of them have been passerines.

04.00 After a bike ride back to the field station it is time to sleep!