birds can be grouped into a number of populations on whether they breed in Britain and on where they over-winter
affects birds present at any given time of year, their behaviour and the methods used to survey them
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Resident Species
e.g., blue ****, tawny owls, wrens, nuthatches, linnets
adults particularly males, defend territory through the winter, though some birds may move southwards (e.g., to the south coast) in the winter before returning in spring
some resident birds such as the robin
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Summer Visitors
E.g., barn swallows, warblers and flycatchers
Summer visitors which breed in the UK but migrate southwards to over-winter in southern Europe or Africa
Generally insect eaters
Arrive in the UK between March and May and depart between July and October. The first brood juveniles are the first to leave.
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Winter Visitors
Winter visitors breed in Northern and Eastern Europe but migrate to the UK and spend the winter here.
Examples include many waders and wildfowl as well as raptors such as the hen harrier and short-eared owl, and flocking species such as redwing and fieldfare, brambling, lesser redpoll
Numbers of some resident birds, such as the starling, blackbird and chaffinch are swelled by visitors from mainland Europe.
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Passage Migrants
Passage migrants are birds which pass through the UK in spring and autumn, migrating between breeding areas North and East of the UK and over-wintering areas further south
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Vagrant and Accidentals
Arrive in the UK occasionally arrive in the uk by accident
Cause lots of excitement for bird watchers
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Global Warming Impact
Global warming is having an effect on bird populations in the UK
Some species such as the blackcap, which were traditionally summer visitors have started overwintering here
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Bird Survey Methods
Birds are one of the easiest groups to survey because they are relatively easy to see and they are highly vocal.
Flocking/colonial species tend to be clumped in their distribution and can be surveyed by simple counting.
Territorial species tend to be evenly distributed through their habitat and are surveyed by territory mapping, line transects or point counts.
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Bird Survey Methods: Counts of Colonies
Useful for species that nest, roost or migrate in numbers
Literally counting individuals
May birds nest in colonies
Some nest on cliffs, on the ground and others in trees
Breeding is synchronised so that all the breeding birds can be counted at the same time
Leks
Some birds show lekking behaviour (black grouse, ruff and capercaillies)
Roosts
Roost communally during the night or during periods when their feeding grounds are inaccessible
Wildfowl and wader counts
The Wildfowl and Wetlands Trust organises counts on the middle Sunday of the month at selected sites throughout the UK
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Territory Mapping
Marking boundaries of their territories with song
Territory mapping is used to determine how many territories of each species there are in a given study area
Large-scale detailed maps are first prepared of the area then a number of thorough vists are made during which all evidence of birds is plotted on visit maps.
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Line Transects
Used to survey birds of open habitats such as moorland, downland, or the open sea.
The surveyor walks (or sails) along the chosen route, recording the birds seen on either side.
Ideally the route should be random rather than following any linear features such as hedge or stream which might affect the species seen.
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Point Counts
A point count is a bird count carried out from a fixed position.
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Bird-ringing Scheme
900,000 birds ringed in Britain
Each ring will have a serial number that can be uploaded to the database.
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