Back at the start of this blog, I wrote about our productive pair of blackbirds from last year, who rebuilt a nest in the same spot as they had three broods in 2019 (they then built a new nest nearby for the fourth brood, rearing 16 chicks in 2019!). Nesting started a bit later this year, and I was wondering if they would repeat the performance. It’s been a bit confusing, but I think we now have an idea of how they have made up for lost time with the late start in 2020 – overlapping broods!

Without any colour marks or rings, it is hard to be certain about the individuals involved, but 'nest 1' was in the beech hedge in our vegetable patch, and the chicks left this nest on the 18^th April. On the same day, we saw a female blackbird on a new nest in a stick pile in our ‘woodland’ area, where we have some hazelnut trees and our chicken run. This is about 20 yards from the other nest.

This new nest held three eggs when checked on the 21^st April, but they were hatching on the 25^th. This meant that incubation must have started around the 12^th April and egg-laying around the 10^th  - the date we ringed the chicks in 'nest 1' and a week before that nest finished. I thought it was possibly the same pair. We had seen the male doing a lot of the feeding of the chicks, especially after they fledged. My partner, Louise, thought it couldn’t be… but we didn’t find another clutch in the beech hedge nest so it was hard to know.

The chicks in 'nest 2' are now close to fledging, and eggs are now reappearing in 'nest 1', so I am certain that it is the same pair and they are overlapping broods!

State of play with 'nest 3' is that there were two eggs there yesterday, three today, and we will see when incubation begins how many they are going to produce in total.  The photos show the large chicks in nest 2 and checking the egg count in nest 3 with a mirror, all taken this morning.

In terms of timings, this is now ahead of where we were last year; in 2019 'nest 1' started in early March, 'nest 2' started around 20^th April, but 'nest 3' started in late May, with a week delay between finishing one and starting the next. That may have been due to the dry conditions last spring, or the fact that they had to rebuild the nest for the third brood, after 2 broods it was in a state of disrepair.

Having started 2 weeks later this year, they are now nearly three weeks ahead of where they were last year for brood three. It may be that keeping to three eggs for the second clutch (last year it was 4 eggs) has been less of a drain on resources. It will be interesting to see if the total production matches last year. I guess they can now switch between the two nests and go for four broods again!

Dr Vince Lea
Head of Wildlife Monitoring 

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