−−− BY LINDA JENKINSON −−−
It’s so good to be back. I hope that you’ve been able to enjoy the lovely birdsong during lockdown. If you have then you’ll have noticed that things have become very quiet now. It’s because the breeding season has ended and each bird has begun its post-breeding moult.
This silence affects me deeply. It feels like I’ve lost my hearing after identifying birds by their song for so many weeks. However, one bird helps me through the silence until the excitement of autumn is upon us. That bird is the swift. As well as teaching people about birds and leading birdwatching trips, I run Leeds Swifts with my friend Martin Calvert. We are part of a national network of swift conservationists and some of us rehabilitate grounded swifts found by the general public.
If a swift is found on the ground it’s in trouble. It can be underweight, dehydrated or injured and chicks will not be adequately developed despite being fully feathered.
There are a lot of urban myths about what to do if you find a grounded swift, from feeding them meat and mealworms to throwing them up in the air to help them to fly. Posts on social media and YouTube only serve to confirm these myths and there’s generally a thread of well-intentioned responses giving advice about what to do. Most of this is not only wrong but very harmful to these poor little birds. Bad food advice creates a chick so deformed it is unable to fly.
Feeding any young bird requires some knowledge about the species, how they are fed by their parents and what happens when the chicks leave the nest. Breeding swifts arrive at their nest sites at the beginning of May. After a couple of weeks getting into good condition, they lay 2-3 eggs which hatch after 18-20 days. Chicks take 6-8 weeks to fledge, depending on the weather, so there is only time to produce one brood. They are very specialised and are fully developed at fledging. They fly straight from the nest and make their way, unaided, to Africa without perching and without any post-fledging care by their parents.
In contrast, house martins arrive in the UK from the end of March and, in good years, can have three broods. Chicks remain in the nest for 22-23 days then become active around the nest performing short practise flights. When they finally leave, they perch close by and are supported for a few days by their parents.
Getting a grounded swift to a swift rehabilitator is their only chance of survival. Swift chicks rely on aerial insects brought in by their parents. Adult birds bring back a bolus of around 300-500 individual insects of many different species. The chicks gape and cover their parents head to receive the food parcel. If the weather is bad, and the parents have to travel further to find food, the chicks can live up to 10 days but become badly malnourished and dehydrated. These birds need critical care. They can’t be fed and must be rehydrated before feeding despite the intense begging by the chick. If we get them past this stage then feeding begins with a special mixture of insects and vitamins. Birds are weighed each day to check their progress.
To ensure that they are able to fly for up to 2-3 years without landing (yes you read that right), a swift needs to have strong pectoral muscles. It exercises in the nest, doing wing flaps and press-ups. When it can support its whole body on its wings for at least 10 seconds it is strong enough. All that needs to happen now is for the wings to get to the right length.
When the chick’s winglength reaches 16cm and projects 3.5cm beyond the tail then it has completed its development. However it may still not be ready. Getting the weight right is crucial for each bird so we keep feeding them as long as we need to. However, once the bird decides to go, its focus changes. It starts scrabbling to escape and uses up a lot of energy. Any attempts to feed them results in the food being passed undigested so once we get a fine spell of weather we release the bird in a location where there is ample food. It’s such a joy to see them go and it’s worth all the time and effort. Find out more about our swift season by visiting the Leeds Swifts Facebook page.
Linda Jenkinson teaches people about birds in and around Leeds. For details of classes email firstname.lastname@example.org or call 07778 768719. Visit www.startbirding.co.uk or Start Birding on Facebook and Twitter