Hello Liverpool Nature Nerds,
Summer is almost upon us and it time for more migratory birds to arrive in the UK from Africa. We’ve had a few already but I for one can’t wait for the swifts, swallows and martins.
These three amazing birds are often confused with each other (I know I always have a problem with their identification, so I want to talk about their differences, distribution in the UK, habits and characteristics.
Swifts (Common swift or Apus apus, order Apodiformes)
These summer visitors are dark, sooty brown all over, with a pale whitish throat and tiny brown feet (which they use primarily for clinging to vertical surfaces). They have long and narrow scythe-like wings and a slightly forked tail. They also have a piercing, screaming call but according to the RSPB they are not noisy at the nest, which are usually holes inside old buildings but also in specially-designed nest boxes. This is why they can been seen flying around buildings or swooping into a crevice to get to their nests, especially during dusk – all the while screaming loudly.
The amazing medium-sized birds are fantastic fliers. They are so good they can even sleep while flying! Swifts will never be seen voluntarily on the ground because they could be vulnerable to accidents and predation. In fact, non-breeding individuals may spend up to ten months in continuous flight.
Swifts in flight. Credit: Warszawska róg Szerokiej w Tomaszowie Mazowieckim w województwie łódzkim, PL, EU. CC0, Public domain, via Wikimedia Commons
They arrive and breed in the UK during summer (April to August) and spend their winters in Africa (south of the Sahara). So, that’s a very long journey from their wintering grounds to us. In Africa, they follow the rain to be able to deal with rapid changes in insect populations.They mostly stick to the southern and eastern parts of the UK but can also be seen in Liverpool. I am almost certain I have seen them flying above my house. However, during the past 20 years, more than half of the UK’s swifts have disappeared in part due to the loss of nest sites in the roofs of buildings.
Some facts about swifts from the RSPB
- The eat flying insects and airborne spiders above 50m, although they can feed lower, especially over fresh-water bodies
- Population breeding in the UK over summer: 59,000 pairs
- Length: 16 – 17 cm, Wingspan: 42 – 48 cm, Weight: 36 – 50 g
- Beak: b
- Natural habitat: u w
- UK Conservation status: Amber
Swifts mature at four years and can expect to survive a further 4-6 years (although the oldest ringed bird, according to the RSPB, lived for at least 21 years). At maturity, they form pair bonds for life and meet each spring at the same nest site. The females lay two or three eggs at two or three day intervals and incubations starts with the first egg, lasting for approximately 19-20 days per egg (incubation can extend by 4 to 5 days due to bad weather). Incubation starts with the first egg, and lasts for 19–20 days per egg, with both adults sharing nesting duties.
Traditionally, they used to nest in crags, sea-cliffs, caves, hollow trees and nest holes made by other birds. However, these have been now replaced by nests made in holes or roof spaces under eaves of houses or churches and nesting boxes – giving them a wider range. Both adults gather nesting material on the wing, including feathers, paper, straw, hay and seeds, and cemented together with saliva. The nests are renovated and reused for many years. They also fight over nest sites, grappling with their feet to eject intruders. Chicks hatch a few days apart and thus are of different sizes, with the adults feeding them on insect food balls. Bad weather can delay their development and fledging by two weeks. They leave the nests at around six weeks in the early mornings and are immediately independent. And within a few days they start their migration back to Africa, in groups with other fledglings.
Sadly, the use of pesticides and habitat destruction has contributed to their decreasing numbers by impacting their food supplies. And the modernisation of building has resulted in a loss of nesting sites. This is why it is important that we help swifts by installing the specialized nesting boxes.
Happy swift spotting!