Why have our migrant birds suddenly gone quiet?

These hot, sultry days in July and August can seem very quiet from a bird watching perspective. Where have all the birds gone?

Willow warbler, Phylloscopus trochilus

These hot, sultry days in July and August can seem very quiet from a bird watching perspective. Where have all the birds gone? Naturalist Ed Drewitt investigates. 

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Back in April and May, our woods were filled with birdsong as a host of summer visitors join with our resident species to create a riot of song, colour and movement. But now it’s almost as if our woods and hedgerows are empty. What’s happened?

Well, many of those migrants are still here, hiding away as they moult their worn feathers after a busy time in the spring making nests, feeding chicks, and defending territories.

As we head into late summer, migrants that are only here for four or five months of the year are beginning to fatten up and head back south for the autumn and winter. Migration never really stops and at key migration places such as Portland Bill in Dorset migrant birds such as willow warblers pop up throughout June and July, though whether they are still heading north or simply moving back south early is unknown.

Swallows and house martins are quite obvious birds in rural areas and while adults may still have broods to feed even into early autumn, most fledged young birds will be congregating together on phone lines during the day and in the evenings use key roosting sites such as a reedbeds before moving towards the south coast and heading across to France and Spain. Swifts pip them to the post and begin moving south from July onwards and the skies above urban areas can seem very quiet once their screaming antics subside.

In woodlands most of the local birds are keeping a low profile, and species such as Pied Flycatchers move to the canopies of the ancient oak trees they favour before moving south and popping up in church yards, gardens and bushes on their way.

The latest research from a project by the British Trust for Ornithology satellite tracking Cuckoos reveals that many spend as little as six weeks in the UK before heading back towards central parts of tropical Africa where they winter. Most cuckoos stop singing around early to mid-June and suddenly disappear. Young cuckoos may still appear in places into August and September, but their parents will already be travelling across the Sahara Desert into Chad and Niger, heading further south towards the Congo and the Central African Republic.

With millions of young migrants out there the period of autumn migration takes place over a few months, but has more urgency as we head into a cooler October. In later July and August onwards sedge warblers, reed warblers, whitethroats, blackcaps, willow warblers, and chiffchaffs will be on the move. Some may still have late young to feed but many will be moving south, often detected by contact calls rather than song. However, some birds such as Chiffchaffs continue to sing even on migration – perhaps to set up temporary feeding territories. Migrants you see locally could have come from a long way north – a willow warbler caught and fitted with a unique metal identification ring in the Highlands of Scotland was re-caught a few weeks later on a nature reserve on the shores of the Severn Estuary near Bristol; and a whitethroat turned up at the same place three weeks after being ringed in Lancashire.

The truth is our countryside is buzzing with our summer migrants. While singing may have subsided, millions of birds that will be wintering in southern Europe and Africa are quietly making their way through our towns and countryside, often under the cover of darkness.

Species guide – where are they now?

Pied Flycatcher: Will be feeding up in the canopies of trees before heading south and turning up at coastal parks, gardens, and cemeteries.

Chiffchaff: Keep quiet in the bushes but may sing or give our their quiet ‘hu-et’ call. Those that overwinter are from northern Europe.

Willow Warbler: Heading south, Willow Warblers have further to travel than Chiffchaffs and winter in northern and western parts of Africa.

Sedge Warbler and Reed Warbler: Skulking in reedbeds but may turn up in gardens and small bushes while on migration.

Blackcap: Those that summer here head off towards the Mediterranean and northern Africa for the winter. Meanwhile, in the winter Blackcaps that appear in our gardens in the winter arrive from the east (mainly Germany).

Cuckoo: Adults head off in early June though some may linger towards the end of July. Although they stop calling their distinctive hawk-like profile can be a giveaway.

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Lesser Whitethroat: Head off in late summer but rather than moving directly south (the route they came) they move east into the Middle East such as Israel before curving round to winter in Chad, Ethiopia and other eastern African countries.