Bird disturbance – causes and impacts
Post on 12-Feb-2016
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Bird disturbance – causes and impacts
Rebecca MoberlyPlanning & Advocacy Lead (Kent, Sussex and Surrey)
Birds and disturbance
• What do we mean by disturbance?• What activities disturb birds?• What are the impacts of disturbance?• Housing, access and disturbance
What do we mean by disturbance?
• Human activity that may influence a bird’s behaviour or survival
What activities cause disturbance?
• Site specific as to where and when they occur
• Difficult to generalise about activities
• Most common on estuaries: aircraft, baitdiggers, vehicles, boats, walkers and dogs
Impacts of disturbance
• Stress• Direct mortality• Avoidance of suitable habitat• Behavioural response• Change in food intake rate
Population consequence?
Interaction of factors
• Baie de Somme, Oystercatchers
• Disturbance influenced mortality only when cockle stocks low
A matter of choice
• By feeding turnstones and then disturbing them it has been shown that the birds that fly away 1st are those that are full…..
• Birds can react as they would to a predator & make choices according to risk
Examples
• Breeding Little Terns: birds avoid busy beaches, signage and wardening leads to increased success
• Breeding Ringed Plovers: avoid busy areas, trampling of nests, marked population consequence.
• Wintering geese & swans: avoid disturbed sites• Wintering waders: mortality in some circumstances
Links between housing, access and birds
• People visit the countryside and coast for a wide range of reasons. Visitors at sites will often be a complex mix of local residents, day trippers and tourists.
• How does housing relate to visitor numbers?
• What is the link between visitor numbers and impacts on bird populations?
When is access a problem?
• Access is important for well-being, conservation, education etc.
• In general, potential threat caused by:– Large groups– Faster moving– Accompanied by dogs– Erratic
• Adverse effect when survival or breeding success affected
• Responses site and species specific
Finally
• Disturbance and urban effects need to be considered in context with other threats
• Climate change may result in different birds present and different access patterns
• Difficult to define specific distances for urban development
• There may be existing impacts from which difficult to separate impacts of new housing
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