It's all been happening in my garden today! You may remember I recently put up a nest box in our oak tree and have been keeping a watchful eye on it each day. There have been a few blue tits nosing about and showing a little interest and gradually they have been getting closer and closer, peering in through the hole. Today I was lucky enough to see not one but two blue tits enter the box fully. The second in was quickly chased out by the first and then the first went back in. I'm really pleased although this behaviour is no guarantee that any birds will actually nest and lay eggs in there but the signs are certainly promising.
I can't help thinking that the oak tree is beginning to resemble the bird equivalent of a high-rise apartment block, as just a few metres above the best box is a smallish hole in the trunk which the pair of nuthatches have started popping in and out of. Today in particular showed them pecking away at the edge, perhaps to shape and deepen the hole enough for a nest. I mentioned this behaviour to my colleague at Pulborough who have me an interesting fact; nuthatches are the only-or at least one of the only-birds who place mud around the entrance and walls of their nesting cavities. I assumed this is done to insulate the nest but after a little investigation, it would seem they do it to seal up cracks inside the holes, create a smooth pocket for resting their eggs on and create a snug cavity that will be too small to allow any large predators in. I will certainly keep my eyes intently peeled to catch this behaviour live-it would be wonderful to witness!
These birds were very pale in colour, with light grey/brown upper parts and creamy yellow lower parts, and at the lowest part of the belly, underneath the tail, there was a slightly brighter yellow patch. The trail itself was reasonably long and the beak small and thin. The only other birds that came to mind as potential positive IDs were the chiffchaff and the willow warbler and I know it's tricky to tell the difference between the two. Looking at my various books, plus a little Googling, I am now fairly certain that they were willow warblers. These are actually on the Amber species status list, so if they were warblers, it was fantastic to spot them; I'm even more certain after looking at various photos and video clips of warblers.
These are all positive signs that we will have an exciting season for wildlife in our garden, fingers crossed!