It's getting late for ringing swifts

On Monday (3rd August) I popped down to a site at Lee-on-the-Solent to ring some Common Swift Apus apus chicks. You may recall the story from last year, but if not that post is here. You may notice that it is nearly six weeks later than the broods I ringed last year, and that is the result of some quite bizarre events. 

I had received the text from Mark, the house owner, back in June telling me that he again had a brood and that they had laid two eggs, and were happily incubating. But on 20 days things went a bit pear-shaped, when what was presumed to be a bird from a different pair entered the box. A scuffle ensued, during which the eggs were displaced from the cup, both birds then left the box. Mark quickly grabbed his ladder and put the eggs back in the cup and before long a bird returned and began incubating. He thought that things were back on track, but then the incubating bird got a bit agitated and kicked the eggs out from under it, breaking one of the shells....all was lost he thought.

Common Swift nestling

Amazingly, the pair or another then relaid, incubated the full term and now have chicks that are three weeks old, so we decided to go ahead a ring them. Two healthy chicks were ringed, one weighing 45 grams and the other 50. Typically swifts fledge after a 22 day incubation period and a 47 day nestling period, which suggests that these chicks will not fledge the nest for another three weeks yet, the latter part of August, by which time they would normally have left the country. It will be interesting to see how these birds fair, and fortunately with the camera in the nest box at Mark's house we will be able to keep an eye on them.

Common Swift nestling

On the way home a made a quick detour to the Haven and bumped into Dan Houghton. There were a few bits a bobs around, the most notable being the 3cy Yellow-legged Gull that has been hanging around for a while, 2 Common Scoter and 48 Mediterranean Gulls of various ages. 

Industrial view of Fawley Oil Refinery from Hill Head

Swifts (and bats) in the Belfry

I was recently contacted by a representative of the RSPB to see if I would be able to help resolve an issue with common swifts getting into a local church. This is an issue that has been happening over the last couple of years; and involves birds from the breeding colony at the church somehow getting into the church itself, becoming exhausted and dying. I was asked to attend because as well as breeding swifts, there are also roosting bats, and it was imperative that whatever plan of action was to be designed, it must help the swifts but not impact on the bats. The church dates from Norman times and is constructed with brick and flint, with a clay tiled roof, the side elevations of the bell tower are clad with wooden shingles and again it has  a clay tiled roof.

Dead Common Swift, Peacock Butterfly wings and Cluster Flies

I had to access the bell tower by-way of a long ladder and a small wooden door, which led to a small set of steps, and then into the first floor of the bell tower. I counted at least five dead swifts scattered in various locations in this area, along with several wings from peacock butterflies and hundreds of bat droppings and cluster flies Pollenia species.

Swift Head positioned upright on a Stone

There was also a reasonable amount of rodent activity in the bell tower, and some of the swift corpses had been eaten. Eerily, the head of one of the dead swifts was upright on a piece of plaster, I'm not really sure whether someone had positioned it like that or it had just ended up like that after being knocked/gnawed by rodents, probably the latter since its beak was missing.

Decomposed Swift with Flat Fly Pupae

I was rummaging around trying to find, where swifts were getting into the tower and how they were getting into the church. But as I was doing so I came across a decomposed swift with several small black pellets lying around it. I have seen these before when I have ringed swifts in the nest and know them to be the pupa of the flat-fly parasite Crataerina pallida which is host specific to swifts.

Crataerina pallida Pupa

The adult flat-fly is a blood sucking parasite which does not lay an egg, instead it broods the eggs internally, lays a fully formed larva that immediately starts to pupate. When the pupa hatches in the following year, it will try to seek out an adult bird or associate itself with a nest. 

I did manage to find how swifts were getting into the church, and have hopefully resolved that problem but will need to go back in the summer and see how they are getting into the bell tower. My aim will be to try a stop the swift becoming trapped in the first place, but in doing that I don't want to stop bats getting in, I will keep you posted....