Blue tits have Excellent Productivity

After an excellent breeding season in our nest boxes with good sized broods and very few dead youngsters we expected good numbers of tits this summer in our mist netting sites. Our predictions proved true and although I have not got full details from all Group members as yet, all report good numbers of young birds, especially Blue Tits during August. For the catch of 240 that I have the data for, the percentage of adult Blue Tits in the catch is very low at just 5% suggesting excellent productivity. This compares with 2015 when after a poor breeding season the adult percentage was 37 % suggesting very low productivity.

Great Tit suggest a similar pattern although we ring smaller numbers (74) but Adult percentage is 16% compared to 31% last year.

Willow Warblers continue to pass through in good numbers, although as would be expected in smaller numbers than mid month but Chiffchaff have increased.

John

Willow Warblers Still on a Roll

A record catch of 88 Willow warblers today at Leighton Moss brought our total catch for the year to 382, 97 more than the whole season in 2015 and they usually continue to pass through to early September. Suggests an excellent breeding season for this species. Included in today's catch was an adult control, will be interesting to see where it originates from. Other birds caught included 42 Reed Warblers and 17 Sedge Warblers, a Tree Pipit and a Whitethroat added variety.

Willow Warblers on a Roll

Our recent catches at Leighton Moss have been dominated by Willow Warblers, partly because the nets in the reed bed have been exposed to wind reducing the catch of Reed Warblers and Bearded Tits but the  nets near willows are more sheltered. However its interesting to compare this years catch with the  same period over the past three years. To date this year we have caught 225, this compares with an average catch of just 107 over the past three years. This suggests good productivity this year in common with many other species. Our local Willow Warblers  have maintained their populations. However ringing recoveries from previous years suggest that  the bulk of the passage population originates in Scotland with 15 recoveries there mainly in the breeding season. We have also ringed more Chiffchaff although their main passage period is usually a little later.
John