Chudleigh hirundine passage

After a dull and damp morning, a brief period of hazy sunshine sent the temperature up from 16 to 19C at 12:25. Within 5 minutes the air was full of Swallows and House Martins and over 600 flew NE in 15 minutes. Movement was leisurely though, most birds apparently feeding as they went. There were slightly more House Martins than Swallows, perhaps 60:40. As I looked through bins at them there were good numbers of flying insects in the air: house-fly types, bumble-bees and even a few crane flies maybe 25m up!

As the rain earlier marked the passage north-eastwards of a warm front (airflow from North Africa?), I wonder whether they were following the front and hence any insects carried up by rising air and/or rising temperature. Although Swifts are known to track weather movements (presumably either to avoid bad weather and/or feed on insects carried by the air mass), and I would guess House Martins might do the same, I've not seen hirundine movements suggesting this before. Clearly, moving NE in October is not logical if you should be making for Africa!

Posted October 8th, 2012 at 3:31 pm by Dave Smallshire in Bird News