Birds to spot before they fly off south

(c) Ray Hennessy 

About a quarter of our familiar birds herald spring when they arrive in the UK to nest and breed. But what happens when it is time for them to leave? By August the breeding season is ending, and their food is running out. Migrating birds – and their young – will depart in autumn for warmer climes (and more insects) mostly to the wetlands of Africa. However, before setting off, many of these intrepid winged travellers will visit the mud flats of Avon’s wetlands to fatten up on insects before starting their epic journey south.


Swallows arrive in April to set up home, building their mud and straw nests on ledges, in farm buildings or under house eaves. Pairs of birds scout several locations before choosing the best. Agile fliers, they spend more time in the air than any other land bird, mating, sleeping and feeding on the wing. They tend to hunt large single flying insects such as horse flies and bluebottles rather than swarms of smaller insects. They leave the country when insects start running out in September and October. Look for flocks of swallows (including house martins, below) at Chew Valley Lake, feeding above the water around the lake in preparation for their 6,000-mile flight to southern Africa.

House martins

A member of the swallow family, these small black-and-white birds also usually make their nests in the eaves of houses. Made of hundreds of tiny lumps of clay and built over three weeks, their communal nests are often luxuriously lined with white feathers. Colonies like to reuse their old nests and often return year-after-year after wintering in Africa. House martins hunt flying insects including mosquitos. In late summer, colonies of house martins gather on telephone wires as they prepare for migration in late-August. If raising more than one brood, some depart as late as October.


Most swifts have started migrating by late-August but deserve a mention because, although unrelated, they are often mistaken for swallows. Like swallows, swifts are aerial acrobats living their life on the wing. However, generally you see swifts in the city and swallows in the countryside. Swifts do not fold their wings into an aerodynamic point behind them as swallows do but outstretch them into the shape of two downturned scythes. Unlike swallows, swifts do not have feet big enough to perch. Look for swifts screaming their characteristic cry above Chew Valley Lake and within the city itself. 

Reed warbler

The reed warbler is completely dependent on reed beds for nesting, returning to the same breeding site each year. A good place to spot them is at Chew Valley Lake and Oldbury Power Station.


These small birds are called waders with long legs to better tread the estuary mud, as they bob up and down looking for lug worms. Arriving in March and April, they leave their watery breeding grounds for southern climes in July and August, with the young following in September. Spot them at Sand Point.