Sunday, May 23, 2010

New Tits

We have now completed checking the 28 tit boxes, all of which were occupied; there was an even split of 14 broods of Blue Tit and 14 of Great Tit.

We were able to ring 25 broods all told, 13 Blue and 12 Great. That's 115 Blue Tits and 73 Great Tits. One brood of Blue Tits had fledged and 2 broods of Great Tit went unringed (making 204 known young).

The average brood size for Blue Tits was 9.1 (range 5 - 11) and for Great Tits 6.6 (range 3 - 10).

The Blue Tits were, as a whole, one week ahead of their larger cousins this year. It is more normal for the larger tit to breed ahead of the smaller Blue Tit, but we suspect that the Blues are set in their ways (according to day-length), while the Great Tits move their laying date (according to the spring season's temperature). However, this spring is generally considered to have started 4 weeks later than in recent years.