The first signs that this was going to be a poor year for Blue Tits came from our nest box studies. Of the 50 pairs that occupied my boxes, laying was 12 days later than average. Brood size was 1.5 young down on 2014 and only 26 of the 50 occupied boxes produced any young. Predation, probably by Weasels played its part but the main reason was probably a shortage of caterpillars at a crucial time due to the cool and wet spring weather.
That this poor productivity has meant lower numbers at all our ringing sites this late summer on. At the site where we catch most blue tits numbers have plummeted. In 2014 we caught 470 birds during the period from early summer to early winter, this year only 209. But even more telling is the percentage of adults in the population. The average over the last 19 years has been 14.5% and in an exceptional year as low as 7%, but this year it is 36% and at another site with smaller numbers ringed it is a high as 55%. Both figures suggesting very low productivity.
On the bright side adults and juveniles from 2014 appear to have survived well at all sites. Our oldest bird this year to date is 6 years and 214 days and we have 3 others at five years. Our record though is 8 years and 15 days. Will be interesting to see what the breeding population is next year.
NLRG was formed in 1957 to help in the study of birds in the Lancaster and District Birdwatching Society area. There are currently 12 active ringers. Species currently being studied include: Pied Flycatcher, Bearded Tit, Sand Martin, Twite, Goosander, Oystercatcher and Grey Wagtail. Migration has been studied for 28 years at Heysham. We welcome anyone who wants to observe, help or perhaps wish to become a ringer. Photo: A Heysham-ringed Twite on the Mull of Kintyre (thanks to Eddie Maguire)
Wednesday, 23 December 2015
Wednesday, 16 December 2015
Quick OfF the Mark
Since its inception the group has ringed a total of 23,608 Sand Martins mainly at the colonies in the sandy banks of the River Lune. To date we have had 48 recoveries on passage through France mainly caught by French ringers, all were of birds caught as adults or juveniles. Of the 48 reported 31 were in July, mainly young birds but because they were caught after fledging we had no way of knowingexactly how long they took to reach France. However this year Dave ringed 56 nestlings at an artificial site and one has just been reported in Northern France just 33 days after ringing. It probably took 5-6 days before it fledged so it had started its migration south about 25-27 days after fledging when it was only about 45 days old. Amazing! It had traveled 493 kms SE when caught. John
Posted by North Lancs Ringing Group at 18:37 No comments:
Subscribe to: Posts (Atom)