Conservation of Migratory Animals

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Conservation of Migratory Animals
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What animals migrate?

• Mammals
• Birds
• Butterflies

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What is migration?

• Migration
• A two-way movement, usually based on seasonality

Wintering Area
Breeding Area
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Kinds of Migration

• Latitudinal (north-south), can be short to long
  distances
• Some whales
• Some bats
• Many species of songbirds, shorebirds,waterfowl,
  hawks

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Kinds of Migration

• Elevational migration
• Movement up and down mountain slopes.
• Examples deer, elk, Mt. Goats, spotted owls,
  some songbirds
• Related to weather (espec. snow depth) and food
  conditions

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Groups of Migratory Birds

• Hunted forms
• Waterfowl shorebirds

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Groups of Migratory Birds

• Non-hunted forms
• Songbirds Raptors
• (most Neotropical migrants)

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How Do We Study Migratory Animals?

• Direct observation
• Capture and mark
• Radar, radio satellite tracking

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How Do We Study Migratory Animals?
Birds

• Direct observation
• Bird watchers
• Wildlife biologists

Bird watchers at Hawk Mt. Bird Sanctuary
(Pennsylvannia)
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An example of a watched migration the
Broad-winged Hawk
A medium-sized hawk from Eastern No. America
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How Do We Study Migratory Animals?
Capture, mark and re-capture
Banding birds
Capturing sea turtles
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How Do We Study Migratory Animals?

• Neotropical migrants

Radar detection of birds arriving near Houston,
TX (images from S.A. Gauthreaux, 1999)
Trans Gulf migrants arriving Apr 25, 0031 GMT
Trans Gulf migrants leaving Apr 25, 0159 GMT
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How Do We Study Migratory Animals Geographical
Positioning System
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What are the issues?

• Neotropical migrants
• trends in numbers

Population trends for the Black White
Warbler from 3 different regions of Eastern US.
And Canada
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What are the issues?

• Neotropical migrants
• loss and fragmentation of nesting habitat
• lower carrying capacity
• reduced reproduction

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What are the issues?

• Neotropical migrants
• loss and fragmentation of nesting habitat
• brood parasitism by brown-headed cowbirds

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What are the issues?

• Neotropical migrants
• loss /change of habitats along migration route
  (stop-over locations)

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What are the issues?

• Neotropical migrants
• winter habitat loss or change

Here is the problem
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What are the issues?

• Example Swainsons Hawk
• Pesticide use in winter range

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What are the issues?

• Example Swainsons Hawk
• Population decline of 90 since 1940s
• Breeding range apparently not the problem
• Counted in migration over Mexico and Panama, but
  where were they headed?
• Satellite telemetry showed that most ended up in
  Argentina - in La Pampa
• Roosted in woodlands around farms - 1,000s of
  hawks in same roost
• Up to 95 of diet is grasshoppers

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What are the issues?

• Example Swainsons Hawk
• Farmers spray crops with monocrotophos to kill
  insects, hawks die from ingesting pesticide
• One six-day survey found 4,000 dead hawks - could
  be killing 5 of population/year
• Farmers dont mind hawks but need to control
  insects - effort to find alternative pesticides
• Use of monocrotophos now down to 2 of previous
  usage

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Conservation and Migratory Stopover Sites
How Important Are Riparian Corridors? -songbirds
Stop-over
Young 1991
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Conservation and Migratory Stopover Sites
How Important Are Coastal Areas? -shorebirds
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Conservation and Migratory Stopover Sites

• Characteristics of stopovers
• Productive habitat - providing rich food
  resources for birds to quickly refuel and move on
  (insects, marine invertebrates, berries)
• Near ecological barriers - coasts and large lakes
  often concentrate migrants at edge of water
• May also be raptor migration path - risk of
  predation
• Conservation of stopovers may be just as
  important as breeding/wintering areas