We previously reported on the behaviour of one of the Landbeach Swifts, Swift 396, in its nest-box on the day that it was fitted with a geolocator, 21st July 2011. We recorded it again on its last day, 28th July 2011, having successfully raised 2 chicks. We were therefore delighted when it reappeared in the box on 12th May 2012. It settled down to breed and we retrapped it to retrieve the geolocator on 21st June. About a week later, the chicks died, probably through lack of food, but both birds continued to visit the nest-box until 28th July, the same date as the previous year.
Since that time, the BTO has published the results of one of the Fowlmere birds retrapped in 2011, and results from birds fitted with geolocators in Sweden have also been published. So now, we can tell the story of the Landbeach geolocator swift.
The journey followed by Swift 396 resembles quite closely a number of other British Swifts. The following is a paraphrase of Chris Hewson's analysis and account of Swift 396 (thank you Chris):
"The positions (yellow symbols) are averages for day & night positions for three day periods, this smooths the data and also compensates for movement between successive dawn or dusk events. Points within 20 days of each equinox are removed, because the determination of latitude cannot be achieved reliably. After 21 April, daily 3-day running averages are shown (i.e. the three day periods overlap by two days) to give a clearer idea of the migration from central through to west Africa. It probably arrived back in Landbeach sometime on 12 May but didn't go back into the box until after dark. The first time one can be sure it was back in the box was 0728 on 13 May but it was probably there in the evening of 12 May.