Dear BTO - part 3

Hospital of St Cross Update - October 2021

At the end of each nesting season we go back to the Hospital of St Cross, Winchester, to check and take photos of the inside of each of the fifteen purpose-made internal Swift boxes that we installed there in the winter of 2018/2019. Because of the exclusion of the Swifts by the erection of stainless steel mesh at the eaves around fifteen years ago, aimed mainly at preventing Jackdaws getting into the loft space, the large number of Swifts that nested here had immediately crashed to just two or three pairs. You can read about our previous blogs on St Cross here and here.


In both 2019 and 2020 two pairs reared young in the boxes and others showed signs that younger non-breeding Swifts had been starting to build nests ready for the following season. Using a combination of both our external and internal observations during the summer, and our later inspection of the boxes, we can confirm that in 2021 eight pairs reared young along the east wall of the Old Kitchen Wing where the boxes are installed. There had been none nesting along this wall since the exclusion took place. Six of these pairs were in the boxes and two pairs, attracted by the calls from the call player were adjacent to or underneath a box! You can read more about this here.

The two or three other pairs still remained in 2021.

Part of the Old Kitchen Wing where internal Swift boxes have been fitted

And I was interested in the fact that although the feathery nest with two eggs was very visible on 9 July on the wall just to the right of box 7, by the end of the season just after the two young had fledged you would have no idea that Swifts had nested at all here at as there was no longer any visible evidence of the nest. Three weeks of the youngsters scrabbling around chasing the adults as soon as they appeared with food meant that the loose detritus on top of the wall was all repositioned and there was no longer even any feathers to be seen!


Nest with eggs 9 July 2021

The same area on 7 Sept 2021

This has exceeded our wildest expectations in just three years. In addition to the birds that reared young, two other boxes now have completed nests and two more have a couple of feathers inside showing that Swifts have entered these.


Box 8 - completed nest Sept 2021

It was also fascinating to see how clean many of the boxes were just after the young had fledged.


Box 1 Sept 2021. Young fledged 3 years running

And it was lovely to discuss and share the results with so many people at the Michaelmas Fair at St Cross on 25th September, and to hear from the Brothers about how many Swifts there used to be here fifteen years ago, before they were excluded from their nesting sites. It was excellent to hear how they so look forward to the Swifts’ return each May and how much pleasure it gives them.


The Hampshire Swifts stand just before opening time.

So what next? We have plans to double the number of internal boxes this winter and have already measured up for these. And we also plan to have two cameras on nests from the start of the season next year so that people can follow their development from the beginning of the nesting season. Roll on 2022.


Dear BTO, no sign of insect decline being the cause of the catastrophic decline in Swifts. Hint - loss of nesting sites is actually the major cause. Lots more Citizen Science to come…


Please correct your website.


Tim Norriss – BTO member


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