This year has been our most successful chough breeding season, thanks to a combination of an increased number of aviaries, and the long hours of constant monitoring. As always, there was a mixture of highs and lows.
The five new purpose-built chough breeding aviaries were finished on time, and the breeding pairs were put in place on Valentine’s Day as planned. This year we had eight pairs of choughs set up in seclusion aviaries, with another pair in our original chough aviary in the main park (first used in 1976). The remaining birds of our flock stayed in the large poyltunnel flight aviaries – where one pair was also successful, and raised a single chick.
The nest box cameras once again proved invaluable, giving us an insight into the normally unseen inside of a chough’s nest. Red-billed Choughs are well known as being an intelligent member of the crow family, and the vocalisations and behaviours continued to delight viewers.
Some of the behaviour was baffling – a male bird removing chicks as soon as they hatched, or another removing eggs. Other behaviour was quite touching. The clip below shows a female laying an egg, while the male waits patiently at the edge of the nest.
Three of the pairs started building nests immediately, and nests were quickly filling up with eggs. At this point, the weather suddenly changed back to winter mode, and the remaining pairs seemed to stall. At the end of March we had the interesting situation of eggs in nests, other nests being built, and some not even started!
The total number of eggs laid this year was forty one – a number we could only have imagined a few years ago. One pair did lay two clutches, which is highly unusual. (However, the male had already thrown out the first four eggs.) This pair eventually laid seven eggs, and produced just one chick.
As the birds had staggered their laying times, we had the benefit of being able to concentrate on any supplementary feeding, chick weighing, health monitoring and nest manipulation.
In mid May Liz Corry & Laura Gardner from the Wildwood Trust came down to take four chicks for the upcoming release in Kent. The four birds were about a week old, and were taken to be creche reared with other chicks, as a large family group. This meant the chicks, while steady around people, would be much less likely to become imprinted on their adopted human parents. It would also make the chicks suitable for very early training for the release later this year.
The final figures – forty one eggs, twenty two hatched, and twelve fledged. The number of eggs laid has been slightly skewed by the pair which laid seven eggs to produce one chick. Almost all of the eggs when checked were fertile, which is a good indication of the health of our flock – now approaching some fifty birds.
Our best year ever – until next year!