Features / Migration
When Do Birds Migrate in the UK? A Month-by-Month Guide
Bird migration is most visible in spring and autumn, but birds arrive, leave and pass through the UK in every month of the year.
Spring migration becomes obvious in March, gathers pace through April and continues into May. Swallows, warblers, Cuckoos and Swifts arrive from the south while winter thrushes, geese and wildfowl leave for breeding grounds farther north.
Autumn migration begins earlier than many people expect. The first southbound waders can return in June, and movement builds through July and August as Cuckoos, Swifts and many other summer visitors depart. September and October bring the broadest overlap between birds leaving the UK, passage migrants stopping on their way south and winter visitors arriving from northern Europe and the Arctic. Migration can remain conspicuous into November.
Movement continues during winter. Cold weather, flooding and changes in food supply can bring birds into the UK or shift them between regions. The timings in this guide are therefore broad patterns rather than fixed dates: latitude, weather and the behaviour of individual species all affect when migration happens and how easily it can be seen.
Choose a month below for the immediate answer, then continue into the guide to see how weather, landscape and migration routes shape what reaches England, Scotland, Wales and Northern Ireland.
Useful immediately
Migration now
September selected. Timing varies with latitude, weather and year.
January — winter birds still move
What’s happening: Most long-distance winter visitors have arrived, but cold, flooding and food supplies can still shift birds across and within the UK.
Arriving and moving. Cold weather on the Continent can bring additional wildfowl into eastern Britain, although species respond differently. Within the UK, Lapwings, thrushes and waterbirds may leave frozen or unproductive ground for milder coasts, open water, flooded fields, parks and gardens.
Early and late month. The date matters less than the weather. A mild January may show little obvious change, while a sudden freeze can alter counts within days.
Where to look. Revisit wetlands, estuaries and soft ground after a marked change in conditions. Record departures as carefully as arrivals. Regular flights between feeding areas and roosts are movement, but not necessarily migration.
Across the UK. Inland wetlands may lose birds when water freezes, while southern and western estuaries or flooded farmland receive displaced flocks. Compare counts before and after the cold spell rather than assuming every large flock has just crossed the North Sea.
Map movements
February — the first signs of change
What’s happening: February may still feel like midwinter, but some wintering birds begin to reposition northwards. The main spring departures are still ahead.
Arriving and moving. Pink-footed Geese move between British wintering regions throughout the season. Some travel north during February, although the main return to Iceland comes later. Other short-distance and partial migrants also shift their ranges. Song and territorial behaviour are signs of spring, but do not prove that a bird has just arrived.
Early and late month. Changes in goose numbers and repeated northbound flights become easier to notice later in the month. A cold spell can pause or reverse that movement.
Where to look. Return to the same goose fields, wetlands or open farmland. Record flock size, direction and time. Several visits reveal more than one flight seen in isolation.
Across the UK. Pink-footed Goose numbers can change between Norfolk, Lancashire and Scottish wintering areas as flocks move within Britain. A long northbound flight may still be a change of wintering region rather than the ocean crossing to Iceland.
Map movements
March — spring arrivals meet winter departures
What’s happening: The first familiar spring migrants arrive while winter visitors are still leaving. March is an overlap, not a single start date for spring migration.
Arriving. Wheatears can appear early in the month. Sand Martins often arrive from mid-March, followed by more Chiffchaffs and the first Swallows. Southern Britain usually sees the change before the north.
Passing and leaving. Some Wheatears continue towards Greenland, Canada or Alaska. At the same time, geese, wildfowl, waders and winter thrushes are heading north. Redwings can remain into April, so winter and spring birds may occur together.
Early and late month. Early March may still be dominated by winter birds and a few early arrivals. By late March, a steady rise across several migrant species tells us more than one unusually early record.
Where to look. Check short grass, coastal fields, reservoirs and wetlands. Look for a rise in numbers or steady directional flight, not only the first individual of a species.
Across the UK. Southern and western coasts often receive the earliest arrivals. East-coast sites show different landfalls, while inland water and short grass reveal birds spreading north. In Scotland, the main rise may lag well behind southern England.
Map movements
April — spring migration gathers pace
What’s happening: April is the main spring-arrival month. Short-distance migrants are joined by birds returning from south of the Sahara, while winter visitors continue to leave.
Arriving. Swallows build in number through the month. Yellow Wagtails, Reed and Sedge Warblers, Common Terns and many other summer visitors return. Whimbrels begin passing north from late April. Some birds stop to breed in the UK; others pause before continuing.
Passing and leaving. Pink-footed Geese return towards Iceland during April and early May. Brent Geese and other winter waterbirds also leave, although some remain into May. Birds are moving both into and out of the UK.
Early and late month. Early April retains much of March’s mixture. Later, long-distance migrants reach more northern and inland habitats. Cold or poor weather can slow the progression.
Where to look. Wetlands, reedbeds, farmland and sheltered coastal cover can all reveal arrivals. Easterly winds may make landfall more obvious on the east coast, but do not guarantee a fall.
Across the UK. South-coast headlands, western islands, east-coast cover and inland wetlands reveal different parts of the same movement. Birds arriving in southern England may still be travelling towards Wales, northern England, Scotland or Northern Ireland.
Map movements
May — late arrivals and birds still heading north
What’s happening: Spring migration is not over when the first Swallows and warblers arrive. May brings later summer visitors and waders still travelling towards the Arctic.
Arriving. Swift arrivals are strongly associated with early May. Spotted Flycatchers are among the later summer visitors, often arriving from late April into May. Numbers may continue to rise well after the first report.
Passing through. Whimbrels and other waders stop on UK coasts and estuaries before continuing north. Some small birds found at coastal sites are also passing through rather than settling nearby.
Early and late month. Early May still has a wide range of arrivals. Later, Arctic-bound waders and the final long-distance arrivals become more noticeable, although timing differs between species and regions.
Where to look. Check estuary edges, short grass, coastal fields, reedbeds and sheltered scrub. A rising tide gathers feeding waders into smaller areas and makes them easier to count; it does not cause their migration.
Across the UK. Estuaries in England, Wales, Scotland and Northern Ireland can all hold Arctic-bound waders. Scottish islands may be among their last UK stopping places, while inland wetlands can reveal passage far from the coast.
Map movements
June — quieter, but not still
What’s happening: Breeding dominates June, so migration is less obvious. Movement has not stopped, but feeding flights and local dispersal are easily mistaken for migration.
Passing and leaving. A few late spring migrants may still be heading north early in the month. Some adult male Cuckoos also leave the UK in June, much earlier than young Cuckoos.
Early and late month. Late northbound passage is most likely early in June. As the month continues, local feeding trips and post-breeding movement become more prominent. Without clear direction, timing or tracking evidence, it is safer to describe these simply as movements.
Where to look. Coasts and estuaries remain the best places to find late passage. Cuckoo tracking reminds us that some departures pass unnoticed from the ground. Regular flights from a seabird colony to feeding areas are daily journeys, not migration.
Across the UK. Late waders can appear from southern estuaries to northern islands. Tracked Cuckoos from England, Scotland and Wales also show that an early departure may begin far from an obvious coastal watchpoint.
Map movements
July — autumn begins during summer
What’s happening: By July, southbound migration has begun even though many birds are still breeding.
Passing and leaving. Waders may start moving south early in the month. In some species, adults and failed breeders leave before juveniles, although the order differs between species. Cuckoos are departing and Swifts begin to leave from mid-July.
Early and late month. Early passage may involve small numbers of adult waders. Later, more species and larger numbers begin moving, while gatherings of Swifts and hirundines become easier to notice.
Where to look. Estuaries, muddy edges and shallow scrapes provide the clearest evidence. Age and plumage matter: a worn adult wader in July tells a different part of the story from a fresh juvenile several weeks later.
Across the UK. Southbound waders reappear on estuaries from the Wash and Thames to Morecambe Bay, the Solway and Belfast Lough. High tide gathers them into view, but reveals the movement rather than causing it.
Map movements
August — southbound migration builds
What’s happening: Several kinds of autumn migration are underway. Waders pass through, Swifts and hirundines leave, warblers feed before travelling south and seabird movement becomes more noticeable.
Passing and leaving. Juvenile waders follow earlier adults, giving some species more than one passage peak. Swift numbers fall quickly. Sedge Warblers and other reedbed birds feed heavily and move south, while Sand Martins are well into their departure period.
Early and late month. Early August still brings many adult waders and plenty of Swifts. Later, juvenile waders and passing songbirds become more prominent, and Swifts quickly disappear from towns and villages.
Where to look. Watch estuaries and shallow wetlands for changing wader ages, reedbeds and coastal scrub for feeding songbirds, and the sky for hirundines moving steadily. At Holme, northerly winds were associated with more Arctic Skuas and north-westerlies with more Great Skuas; the useful wind depends on the species.
Across the UK. Estuaries and wetlands reveal the change in wader ages throughout the country. Reedbeds and scrub hold feeding songbirds, while Atlantic and North Sea watchpoints expose different seabird movements.
Map movements
September — birds coming and going
What’s happening: September brings one of the widest overlaps of the year. Many birds are heading south while the first large numbers of winter visitors arrive.
Passing and leaving. Most Reed Warblers leave during September. Sand Martins, other hirundines and many small birds continue south, while wader passage remains active along coasts and estuaries.
Arriving. Pink-footed Geese begin reaching the UK from Iceland and Greenland around mid-month. Redwings often start to arrive during the second half. Birds arriving for winter may share a site with birds leaving for Africa.
Early and late month. Early September is mainly about summer visitors leaving. Winter arrivals become more important later, although weather and food supplies affect how obvious they are.
Where to look. Listen for calls overhead and note the direction of morning flights. Check estuaries, coastlines, reedbeds and inland feeding areas. A sudden coastal gathering may have just landed, but not every increase is a major fall.
Across the UK. North Atlantic arrivals are often conspicuous first in Scotland before some populations move farther south. Western islands, eastern headlands, estuaries and inland wetlands each reveal birds from different source regions.
Map movements
October — winter arrivals take over
What’s happening: October is one of the most conspicuous migration months across the UK. Birds arrive from the north and east while the last main wave of summer visitors continues south.
Arriving. Fieldfares often begin reaching eastern coasts early in the month. Redwings continue to arrive, joined by Blackbirds, Song Thrushes, finches and Goldcrests from northern and continental Europe. Geese, swans, ducks and other waterbirds settle into their UK wintering areas.
Passing and leaving. Swallows, Redstarts, Reed Warblers and other summer visitors may still be moving. Before calling one exceptionally late, check the normal departure period for that species.
Early and late month. Early October retains some of September’s two-way movement. Later, winter arrivals and visible late-autumn migration become the main story.
Where to look. Listen above coastal hedges and woodland, not only at eye level. Calls may reveal birds passing after a sea crossing. Seawatching advice must remain species- and coast-specific rather than being reduced to one useful wind direction.
Across the UK. East-coast cover reveals North Sea landfall; northern and western coasts receive Atlantic arrivals; estuaries, firths and farmland show birds settling into winter. A large fall requires the right journey, timing and weather.
Map movements
November — arrivals settle into winter
What’s happening: Late autumn is turning into winter. Migrants are still arriving, a few summer visitors are still leaving, and many birds are moving into the places they will use through the colder months.
Arriving and passing. Blackbirds, Fieldfares and Goldcrests can still arrive in good numbers. November is usually the main arrival month for wintering Woodcock. Great Northern Divers also begin appearing around UK coasts during October and November.
Leaving and moving. A few Hobbies and other summer visitors may remain, but are now unusual. Woodpigeons provide a more obvious movement within Britain: from late October through much of November, large flocks may fly high and south on clear days. Where all of them go is still not fully understood.
Early and late month. Long-distance arrivals can remain active early in November. Later, winter settlement and weather-driven redistribution become more important.
Where to look. Watch woodland edges, coastal cover, open sky and wetlands. Repeated counts help separate arrivals from birds commuting between established feeding and roosting sites.
Across the UK. Northern firths, east-coast woods, western bays and southern headlands show different parts of the change from arrival to settlement. Seawatching still depends on species, coast and conditions.
Map movements
December — winter movement
What’s happening: Long-distance migration is quiet, but birds are not fixed in place. Food, frozen water, flooding and shelter continue to change their distribution.
Moving within winter ranges. Redwings and Fieldfares may enter parks and gardens when frozen ground makes feeding difficult. Lapwings can move to flooded or coastal ground, or travel much farther during severe weather. Ducks and other waterbirds respond differently: cold may bring some into the UK while pushing others south or west.
Early and late month. Conditions matter more than the date. A mild December may produce little obvious movement, while several hard frosts can shift birds quickly.
Where to look. Revisit familiar wetlands, estuaries, farmland and berry crops before and after a marked weather change. Record what has gone as carefully as what has arrived. An evening roost flight is not the same as a wider regional movement.
Across the UK. Open water, Atlantic coasts and sheltered estuaries may receive displaced birds when inland ground freezes. A thaw can reverse the pattern, so direction and repeated counts matter more than one large flock.
Map movements
How to use the East Anglia inset: the inset remains because it shows one familiar place where landfall, staging, settlement and local redistribution can be compared. The monthly text ranges across the UK; the inset is a field example, not the centre of British migration.
Read a text description of the monthly map
Britain sits where several migration systems overlap. Broad population-level bands connect it with Iceland, Greenland and the North Atlantic; Arctic Scandinavia, the Baltic and northern Europe; western Europe and Iberia; and West and central Africa. Monthly examples range across England, Scotland, Wales and Northern Ireland. The East Anglia inset is one observation lens, not the destination of every movement. The selected overlay changes with the month; every visible movement is also named in the adjacent controls.
What migration means in Britain
Migration is a regular movement between different parts of a bird's yearly range. Distance is not what defines it. A Cuckoo travelling between Britain and central Africa is an obvious migrant, but a Golden Plover moving from an upland breeding ground to a lowland wintering area is migrating too.
The usual labels are helpful, but they describe a population at a particular time rather than a permanent feature of the whole species.
A summer visitor comes to Britain mainly to breed and spends the rest of the year elsewhere. Swifts and many warblers fit this pattern. A winter visitor, such as a Pink-footed Goose from Iceland or Greenland, breeds farther north and spends much of the colder season in Britain.
A passage migrant is travelling through the place where you see it. Britain may be the final destination for one population and a stopping place for another. British-breeding Wheatears return in spring, while larger northern Wheatears may continue towards Greenland. Whimbrels feeding on an English estuary may still have a long journey north ahead of them.
With partial migration, some birds in a population migrate while others stay closer to the breeding area. Blackcaps wintering in Britain may include continental birds travelling north-west, while many Blackcaps that breed here head south. A Blackcap in a January garden and one singing in May may belong to different populations.
Dispersal means moving away from a breeding or birth area rather than making a regular seasonal journey. Young birds leaving where they hatched, failed breeders moving to a new feeding ground, and seabirds travelling from a colony to feed are all moving, but they are not necessarily migrating.
An irruption is an irregular movement that can change greatly from one year to the next, often because food has become scarce farther north or east. Waxwings are the familiar example. When northern berry crops are good, few may reach Britain; when food fails, many more travel west or south.
These terms help us ask better questions. Where might the bird have come from? Is it likely to continue? What would separate migration from an ordinary local flight?
Britain between the Arctic, Europe and Africa
Britain lies beside the Atlantic and North Sea, just west of mainland Europe and between very different breeding and wintering areas. This gives it several overlapping migration routes rather than one simple British flyway.
To the north and north-west, Britain connects with Iceland, Greenland and the wider North Atlantic. Pink-footed Geese arrive from Iceland and Greenland in autumn. Waders, swans and other waterbirds link northern breeding areas with particular British estuaries and wetlands.
Across the North Sea lie Scandinavia, the Baltic and continental Europe. Thrushes, finches, Woodcock, wildfowl and many other birds cross to eastern Britain in autumn. Birds cross in the other direction in spring. Radar studies show that much of this travel happens at night in favourable winds and steady weather, unseen from the ground.
To the south and south-west, Britain connects with western Europe, Iberia and the Mediterranean. Some short-distance migrants spend winter within Europe, while many summer visitors continue into Africa. They may travel through Iberia, Italy or the Balkans. The broad bands on a map bring together many individual journeys; they are not roads followed by every bird.
Beyond the Mediterranean, British migrants reach the Sahel, West Africa, central Africa and farther south. Stopover sites, desert crossings, seasonal rain and winter habitat all affect whether a bird returns the following year. The months away from Britain are not an empty gap in its story.
A flyway is the wider system linking breeding, resting, moulting and wintering areas. Its edges are not fixed. Populations overlap, individuals vary and routes can change. Britain is part of several Atlantic and African–Eurasian flyway systems at once.
Different parts of the UK reveal different parts of this system. Northern and western islands receive North Atlantic migrants; east-facing coasts reveal North Sea crossings; estuaries and firths gather waders, geese and wildfowl; inland wetlands, valleys and uplands show passage and seasonal movements away from the coast. East Anglia is one useful window, alongside places from Shetland and the Outer Hebrides to the Severn, Morecambe Bay and Belfast Lough.
Spring migration: arrivals, passage and departures
Spring migration is often described as the return of summer visitors. In reality, three things happen together: birds arrive to breed in Britain, others pass through on their way farther north, and winter visitors leave for Iceland, Greenland, Scandinavia or Arctic Russia.
The change happens in stages. Short-distance migrants and the first long-distance travellers appear in March. April brings a much wider arrival, while May still has late arrivals and Arctic-bound waders. Southern Britain usually sees migrants earlier than northern areas, although each species moves at its own pace.
Weather affects both the journey and what we see. Favourable winds and steady high pressure can support large movements over the North Sea. Poor weather may delay departure, bring birds lower or force them to rest near the coast. A headland full of new arrivals is therefore the result of migration, recent weather and the birds' need to recover.
Spring is often faster and more tightly timed than autumn. Birds need to reach breeding areas, find territories and make use of a short northern summer. An empty reedbed can hold singing warblers a week later. Even so, one early bird tells us less than a steady rise across several sites.
Rare birds sometimes travel beyond their usual range, but overshoots are a small part of the wider story. The main spring movement is the broad return of hirundines, warblers, terns and chats.
Across the UK, watch how the movement advances and spreads. Southern and western coasts often receive early arrivals; east-coast cover reveals different landfalls; inland wetlands and short grass show birds moving on; northern England, Scotland and the islands reveal the later stages. Northbound waders and departing geese also remind us that spring is not only about birds arriving from the south.
Autumn migration and winter arrivals
Autumn is not simply spring in reverse. It starts while summer is still underway, lasts for several months, and includes the year's young birds. Adults and juveniles may leave at different times, and failed breeders can set off while other birds are still nesting.
The first waders begin moving south in June or July. Swifts start leaving from mid-July. Wader and songbird passage grows through August, and September combines strong southbound movement with the first winter arrivals. Thrushes, finches and waterbirds become more noticeable in October, while November still has arrivals and visible migration.
Local movement after breeding makes the picture harder to read. A young bird leaving where it hatched, a family moving to better feeding ground and a long-distance migrant may appear together. Direction, age, time of day and repeated counts help separate them. One flock rarely gives the whole answer.
Weather changes how visible migration becomes. In calm conditions with a following wind, birds may pass high overhead at night. Rain, cloud or a weather front may bring them lower or stop them near the coast. A fall on the east coast needs the right journey and the right conditions; easterly wind alone does not guarantee one.
Winter arrivals add movement in the opposite direction. Pink-footed Geese come from Iceland and Greenland, while thrushes and finches approach eastern Britain from the Continent. British breeders may still be heading south at the same time. Later, clear long-distance movement gives way to birds settling and shifting in response to winter weather.
These layers become visible in different places. Atlantic islands and headlands show departures and arrivals from the north and west. North Sea coasts reveal continental landfall. Estuaries and firths gather waders, geese and wildfowl, while inland farmland and wetlands show birds settling or moving during hard weather. East Anglia supplies several strong examples, but each is part of a wider UK pattern.
How weather and landscape reveal migration
Weather does not cause migration, but it changes when birds leave, how high and fast they fly, whether they are pushed off course and how easily we can see them.
Wind: think about where the bird is going
A following wind makes a journey easier. A crosswind may push a bird away from its intended track. Near the coast, wind can also bring seabirds close enough to see without changing their overall journey.
Ask three questions: where did the bird probably start, where was it heading, and did the wind help, hinder or make it visible? The answer will be different for a Scandinavian thrush flying west, a British warbler heading south and an Arctic Skua following the coast.
Records from Holme Bird Observatory show how specific this can be. Arctic Skuas were most often seen in northerly winds and usually travelled west in autumn. Great Skuas were most often seen in north-westerlies. That is useful local advice, not a rule for every seabird or every coast.
Rain, cloud and weather fronts
Many small birds migrate at night. In good conditions they may pass high overhead and continue inland without being noticed. Poor visibility, rain or a weather front can interrupt a sea crossing and bring them down near the coast. The birds found in the morning may be only a small visible part of a much larger movement.
Do not assume that any birds found after rain are migrants. Look for several signs together: new calls, a mix of species in sheltered cover, tired birds feeding and a clear change from the previous day. Ringing, radar and repeated observations can provide stronger evidence.
Coasts, islands and headlands
Birds do not all follow the coast like a marked road. Some cross it, some arrive from offshore, and others follow it when open water blocks their preferred direction. Headlands and islands can bring these choices into a smaller area. They also give birders a clear horizon against which steady flight is easier to see.
East-facing coasts are important for arrivals from northern and continental Europe. Western coasts and islands reveal different Atlantic movements. A national picture needs both.
Estuaries and tides
Estuaries provide food and safe roosts for birds from many different breeding areas. As the tide covers the mud, waders move towards the remaining feeding edges and roosts. This gathers them into view and makes changes in age, plumage and numbers easier to spot.
The tide does not begin the long-distance journey, and a flight from mudflat to roost is not migration. Repeated counts, colour rings and the arrival of new age groups tell us more about passage.
Valleys, ridges and inland water
Birds may use broad features of the landscape, but one local flight line is not necessarily a national corridor. Reservoirs, flooded fields and river valleys often give migrants somewhere to rest, feed or regain their bearings. They can reveal migration far inland because water and open ground are scarce nearby.
Migration at night
Flight calls can reveal thrushes, waders and other migrants passing over a garden that seems quiet by day. Sound recording can help identify species. Radar is better at showing the scale, height and direction of movement, but usually cannot identify every bird. The two methods answer different questions.
For everyday field use, listen on suitable nights, note the time and weather, and check the area again the next morning. A call tells you that a bird passed overhead. It does not tell you exactly where the journey began or will end, but it still makes the night part of the migration calendar.
Three tracked journeys, three different lessons
Tracking can show where birds go, but the method matters. Satellite and GPS tags can return a series of accurate positions. Small light-level geolocators give a broader estimate and usually have to be recovered from the bird. Ringing builds a long history of connections between places, although recoveries are uneven. Counts show where birds gather, but not the exact route each one took.
Cuckoo: two routes to the same wintering area
Researchers tracked 42 adult male Cuckoos tagged at nine sites across England, Scotland and Wales, recording 56 autumn journeys between 2011 and 2014.
They followed two broad routes. Some travelled south-west through Iberia and western Africa, while others went south-east through Italy or the Balkans. Both groups eventually reached the same wintering area in central Africa.
The study found links between route, survival and changes in local populations. But the sample was made up of tagged adult males, not every British Cuckoo. The map therefore shows broad route bands rather than exact tracks for the whole species.
Pink-footed Goose: a North Atlantic population across Britain
Pink-footed Geese breeding in Iceland and Greenland spend winter in Britain. Ringing, counts and GPS tracking reveal several kinds of movement: the crossing from the North Atlantic, travel between British regions, daily flights between roosts and feeding fields, and the return to Iceland in spring.
The population is spread among major wintering areas in Scotland, Lancashire and eastern England, including Norfolk and the Wash. Numbers at one site can therefore change because birds have moved within Britain, not because the whole population has just arrived or departed. These Icelandic and Greenland birds must also be kept separate from the Svalbard population, which uses wintering and stopping places in continental Europe.
Blackcap: one species, several strategies
Some Blackcaps wintering in Britain and Ireland breed in continental Europe and migrate north-west. Many Blackcaps breeding in Britain travel south or south-west, while others remain farther north than the old label of “summer visitor” suggests.
Geolocators show broad origins and strategies rather than exact satellite tracks. The map therefore uses overlapping areas and general directions. Garden feeding and milder winters are linked with the growth of the British wintering strategy, although individual birds still behave differently. Our feature on why Blackcaps now spend winter in Britain examines that evidence in more detail.
These three examples need different kinds of map. Cuckoos suit broad route bands, Pink-footed Geese suit connections between populations and regions, and Blackcaps suit overlapping strategies. Using the same neat arrow for all three would make the evidence look much simpler than it is.
Conservation across the whole journey
A bird may return to well-protected breeding habitat in Britain and still decline because another part of its year has changed. It may leave in poor condition, lose a resting place in Europe, face a drier season in Africa or find less food on its wintering ground. The problem may be far from the place where the bird is counted.
Tracked Cuckoos make this clear. Birds using two different autumn routes reached the same wintering region in central Africa, yet survival differed before they had completed the Sahara crossing. The study did not point to one damaged site, but it showed why changes on British breeding grounds could not explain everything.
Waterbirds present another problem. Their winter ranges shift with weather and climate, so a network of wetlands matters more than one site. Counts across several countries are needed to tell the difference between a falling population and birds moving farther north or east.
Birders can help by submitting complete lists and counts, following access restrictions and avoiding unnecessary disturbance to tired or roosting birds. Supporting work across whole populations and linked sites also matters. The bird in front of us may depend on places thousands of kilometres beyond the hide.
What to notice on your next visit
Choose a familiar place and keep the comparison simple. Which birds are new? Which have gone? Are birds flying in a steady direction? Have the weather, tide or food changed? Remember to listen overhead as well as searching the habitat in front of you.
One visit can suggest migration. Regular visits make the evidence much stronger. The great value of a local patch is not that it receives every spectacular movement, but that you know it well enough to notice when the usual pattern changes.
Continue reading: compare the evidence in Why Blackcaps Now Spend Winter in Britain, explore the science in our review of Ian Newton's Bird Migration, or see how autumn movement changes a day in the field with the North Norfolk autumn itinerary.
Sources, method and review
This guide uses BTO BirdTrack seasonal summaries, the EURING Eurasian African Bird Migration Atlas, current WeBS and Goose & Swan Monitoring Programme reporting, bird-observatory analysis and the original tracking studies listed below.
The monthly timings describe patterns seen across several years, not a forecast for a particular year. Examples range across the UK. The bands on the maps show broad population-level connections unless a caption says that tracked journeys are being shown. The East Anglia inset remains as one field lens and does not imply that every British route passes through Norfolk or Suffolk.
Information checked: 30 August 2026
Recommended full review: yearly, or when important new tracking, atlas or monitoring work changes the picture.
Selected evidence and further reading
- BTO spring migration overview
- BTO autumn migration overview
- EURING Eurasian African Bird Migration Atlas
- Waterbirds in the UK 2024/25
- Seawatching at Holme Bird Observatory
- Hewson and colleagues: tracked Common Cuckoos
- Lovas-Kiss and colleagues: GPS-tracked Pink-footed Geese
- Blackcap wintering origins and migration strategies
- Manola and colleagues: weather and North Sea migration
- AEWA Conservation Status Report 9
- Natural Earth public-domain map data