A few evenings ago I had the most amazing opportunity to ring some swift pulli (a young bird or nestling that is not yet able to fly) from a families 5 swift boxes!
Out of 6 boxes, 5 were being used and had chicks – I rang 5 chicks and also one adult that we saw fly into a box, and managed to catch (you can see it’s mouth stuffed of insects ready to feed its young!)
Swifts mature and breed when they are four years old – those that survive the hazardous early years can expect to survive a further 4-6 years. The oldest ringed bird lived for at least 21 years! Because of their mastery of the air, swifts have few predators, meaning they are long-lived birds, reflected in the fact that they lay just two or three eggs in a clutch, and only attempt to rear a single brood a year!
Swifts pair for life, meeting up each spring at the same nest site. They normally lay two or three eggs at two or three day intervals with incubation starting with the first egg, and lasts for 19–20 days per egg. The adults share all the nesting duties equally.
The young hatch a couple of days apart, so in the first week the young are different sizes. They grow rapidly on a diet of insects brought to the nest by the parents in food balls.
At two to three weeks of age the young swifts start to move about the nesting chamber and exercise their wings by performing ‘press-ups’ on their wing tips! In a good year the young develop quickly, and are ready to fly at about six weeks old. They usually leave the nest in the early morning, and will be independent immediately. Within a few days of leaving the nest they will start their flight to Africa in the company of other fledglings!
It was an amazing experience and I hope to ring more of these stunning birds next year!