I was really pleased to be joined by Rosie for the entire session today. Usually she arrives, helps me set up, rings a few birds and then heads off to work. Due to circumstances beyond her control, her planned work for the morning had to be postponed, so a full session it was.
We set the same nets as last time: around the feeding stations and a dog-leg around the corner of one of the ponds, six nets, a total of 84m. It was a decent session numerically, not so good for variety. The list was: Blue Tit 32(11); Great Tit 9(4); Coal Tit 1(2); Marsh Tit (1); Robin (2); Goldcrest (1); Chaffinch 1. Totals: 43 birds ringed from 4 species and 21 birds retrapped from 6 species, making 64 birds processed from 7 species.
We are missing a whole chunk of species I would normally expect to catch: Nuthatch, Treecreeper and Great Spotted Woodpecker. The latter were heard all morning, both calling or drumming, but they are clearly ignoring the peanuts so far this winter. We haven’t caught any at Red Lodge, Webb’s Wood or Ravensroost Wood this winter, and only four at Somerford Common. Nuthatch has been better in the forest but the last ones at Red Lodge were at the end of November. Treecreeper have been regular in Red Lodge, just absent for this session.
As for finches: both Lesser Redpoll and Siskin have been non-existent in the forest so far this winter. We have ringed one Chaffinch per session at Red Lodge over the autumn and winter, and it was the same today. Unfortunately, as usual, we caught two but one was suffering from FPV and could not be ringed. This is the one that was:
I think that the Blue Tit catch is the highest single species proportion I have ever had in a catch. What I find remarkable is that there are still so many Blue Tits to be ringed. I fully expect to get good numbers of recaptured Blue Tits: we ring the same places, with the pretty much the same net positions for each site, on a regular basis. However, this constant throughput of new Blue Tits to be ringed is surprising. A key part of that is the seasonality of ringing adult Blue Tits. We ring relatively few adults during the spring and summer, with the numbers increasing in the autumn and maximising in the winter:
When you compare that with the juveniles ringed, there are obvious differences, particularly once the breeding season offloads this year’s crop of youngsters into the mix. For the sake of trying to keep the figures consistent, I have included the previous year’s offspring as “juveniles” for the spring, although they are better described as second year birds.
As you can see, there are still far more juveniles ringed in each season than adults, which is why it is somewhat surprising that, in these regularly ringed woodlands, there are still so many adults being ringed over the autumn and winter season. When you look at my previous post on the movements of Blue Tits around the Braydon Forest, the question has to be: where do these birds come from?
For the sake of this analysis, the seasons are defined as follows: Winter = December to February inclusive; Spring = March to May inclusive; Summer = June to August inclusive; Autumn = September to November inclusive. As a general rule, numbers start to build up in the autumn, peak significantly over the winter and are virtually non-existent during the breeding season / summer.