Naomi Davis, volunteer at RSPB Ynys-hir summarises how the nest box survey and other nests has gone this year...
Small nestbox monitoring comes to an end for another year. The late cold-snap pushed back the breeding dates of the blue and great tits to coincide with the pied flycatchers, normally the tits nest 2 weeks earlier, but didn’t appear to affect our later continental migrants too badly. Our woodlands of ancient oak provide perfect natural nest sites for pied flycatchers, but they will readily take to boxes in patches of younger trees or conifer. Due to the inaccessible nature of the natural nests the best way we can monitor breeding in our birds is to use nestboxes.
We had 35 nesting attempts by pied flycatchers in boxes, and just over half the broods successfully fledged. Sadly the pieds, as well as blue and great tits, came under attack by nest predators; barely a single nest survived in one particular wood. So whodunnit? What we know is the predator in question was meticulous enough to find multiple boxes and has a territory large enough to cover the woodlands of the blue trail. My best guess is a weasel. These are known opportunists, smart enough to recognise a nestbox and to remember sources of good prey year on year. The same area of woodland suffered a few losses last year from a weasel, I know because I found it in a box munching on some pied flycatcher eggs!
In happier news, I was quite surprised to find 3 boxes occupied with wren nests this year, something I’ve not come across before. The entire box is stuffed with moss and a small chamber created inside for the young. This brood is quite close to fledging and I’m glad I got to see them before they moved out.
Nestboxes are fantastic in that they allow us a unique insight into the world of birds, but only a small portion of our birds will use boxes, so what about everything else? The oystercatchers returned to their preferred nesting spot atop the wall by Domen Las hide; 3 eggs produced 3 young which all survived through to fledging! As I write another pair has setup shop on the wall again and is currently brooding 3 eggs.
We’ll have to see what nesting late in the season will mean for that plucky pair. A pair of blue tits nested in our nest-cam box just outside the visitor centre, and many enjoyed watching the attentive pair caring for their five chicks which all fledged successfully.
This year I was lucky enough to find a few different “wild” nests around site, most notably (and audibly) 3 great-spotted woodpecker holes containing some very noisy young. One tree in particular became a temporary visitor attraction being right next to the path on the green trail – just shows how close you can get to the wildlife here!
My first find was a song thrush, their nests are very similar to those of the blackbird but the song thrush lines their nest with muddy clay to create a firm base onto which she lays her beautiful blue eggs. 4 chicks fledged from this nest, what a difference 2 weeks can make!
The best nest treat this year however was won by the humble pair of blue tits who chose to nest inside a broken bow of an oak right next to Ynys-hir hide! Watching the frantic antics of the parents from less than 4 feet away definitely proved a hit with visitors.