Yet another season has come and gone, I remember reviewing last year, it all comes round so fast and it makes you realise just what a massive commitment breeding is, especially when you get juveniles that linger.
Of the sites that I am involved in or monitor, they produced 36 fledged juveniles from 17 sites, giving a slightly better success rate than 2020, 30 fledged juveniles from 17 sites.
Occasionally for different reasons, like essential refurbishment works to the ‘core’ site, they may not breed, this happened on one site in 2020 but such is the bond and link to the building/structure, they were straight back on it in 2021, resumed and fledged 4 young.
Nest box – 6 pairs (19 juveniles)
Tray – 2 pairs (7 juveniles)
Natural – roof/ledge substrate – 4 pairs (10 juveniles)
Did not breed – 5 pairs
Not a bad total and up on 2020 in regards to fledged juveniles, there is going to be ups and downs in every year, if they bred to their full potential it could easily be 50+ juveniles fledged.
In regards to new nest boxes, occasionally newly placed boxes are ignored and you look for reasons why, more often than not, it is down to positioning, even if desperate for a nest site. For instance with Paul and Shaun, we placed a nest box at one site, targeted for the 2019/20 breeding season and it was totally ignored in those years, but was then accepted in 2021 and they bred in it fledging 2 juveniles. Sometimes the structure/layout of the building dictates position and you have to go with it, it’s not always to your liking but it’s obviously better than no box at all and gives them a chance.
At another site, I placed a nest box, aimed at the 2021 breeding season and it was not favoured or used at all, in this case they used ‘natural substrate’ on a ledge and bred. However this year after breeding, they are in and out of it no end and signs look very promising.
However most have been accepted thankfully and many of the boxes are now getting old, the Battersea Power Station box is 9 years old and I have another box at another site, 10 years old. 12mm ply does not last even if you keep weatherproofing it, eventually it will flake. However it is the easiest to make, the cheapest material and it really becomes expensive if you look for alternatives.
Once you get into the realm of cardboard composite, plastic moulds etc, the cost and expense go’s right up.
All in all another good year and very shortly, it will be time to start visiting them all in January for a final check/clean up before yet another breeding season.