Nest predation

nest-predation2

While everything has been going well with the Dutch kingfishers, on the Trent things have taken a disastrous turn. My local birds appeared to have been running about 2 weeks behind the dutch birds and I was expecting to see fish being taken into the nest this weekend. On arrival this morning at the nest site I sensed something was wrong, both birds were outside the nest flying upstream and downstream and perching below the nest borrow entrance. The female wouldn’t enter the burrow, and while the male entered, he came out immediately.

My usual viewpoint is on the opposite bank from the nest, so I had to drive and walk across a field to access the nest bank. As soon as I arrived I could see that the nest had been dug out from above, there were egg fragments on the ground, and a hole going straight down to the nest chamber, which was about 10 inches below the surface.

nest-predation1This has happened before at this site, in 2011 the same thing happened, so I had placed a metal grid above the nest chamber for each of the last two years. The metal grid I’d placed above the nest this year looks like it was just a bit too far back, and the unknown predator had dug down at the side of it. I’d assumed the nest would be about 3ft from the bank face, but unfortunately it was only about 18 inches deep, so it remained exposed, despite my efforts to protect it.

I had thought that it was the noise of chicks in the nest that might bring about this type of raid, however, this nest obviously still contained eggs, so I’m assuming that the predator was using scent. It’s probably fair to assume that the regurgitated pellets that the kingfishers use to line the floor of the nest chamber must have a fairly pungent scent.

The only positive I can take from this is that both adult birds appeared to be fine. If they dig a new burrow I will use a larger grid to try and ensure that the burrow is protected. It does concern me though, that if this has happened twice in three years at this location, how often is this happening at un-monitored kingfisher nests along the river.

A new burrow


It’s just over a week since the first brood fledged and the adults are engaged in excavating a new burrow. It’s come as a bit of a surprise to me, as the female seemed to have settled on an existing burrow about 6ft to the right of the one that the first brood were raised in. She’d been spending a lot of time in this burrow, and I’d seen the adults mating again over a week before the first brood fledged (I was beginning to wonder if they were getting a new brood underway before the first one had even fledged). I have no idea why they’ve decided to dig a new burrow after seeming to commit to the old one, but it looks like the new burrow is going to be home to the second brood and I’m waiting now to see when they settle back into the behaviour patterns typical during egg incubation.

While the burrow is under construction, both birds spend the majority of their time at the nest site. The bird that is not digging stands vigil nearby and emits occasional calls which are quite subdued in comparison to their normal call, this presumably lets the bird in the burrow know that they are present and that all is well outside. When the bird in the burrow emerges, the other often flies straight into the burrow, seemingly keen to see what the other has accomplished and do some work themselves.

Another thing I’ve noticed during this phase is that the male seems very keen to pass fish to the female, but for the time being she’s clearly not interested. I assume the fish passing, and any subsequent mating is on hold until she is happy with the new burrow.

During the time I’ve spent observing the digging of the new burrow, I’ve also seen kingfishers flying past the nest site at speed, occasionally prompting a response from the resident adults. I can only assume that this is one or more of the fledglings; I wonder how long their presence in the adults territory will be tolerated.