Wildlife Tagging SVN3E
Sampling Wildlife It can be difficult to make an exact count of the populations of animals, birds, and fish that move around their ecosystems.
Sampling Wildlife Scientists make their estimates of wildlife populations using capture-mark-recapture sampling. No animals are harmed in this sampling!
Sampling Wildlife First, a sample is captured and marked.
Sampling Wildlife There are many different kinds of capture methods, including: Aquatic dip nets (used in shallow water) Aquatic dip nets (used in shallow water)
Sampling Wildlife There are many different kinds of capture methods, including: Aquatic dip nets (used in shallow water) Aquatic dip nets (used in shallow water) Mist nets (used for birds and bats) Mist nets (used for birds and bats)
Sampling Wildlife There are many different kinds of capture methods, including: Aquatic dip nets (used in shallow water) Aquatic dip nets (used in shallow water) Mist nets (used for birds and bats) Mist nets (used for birds and bats) Helicopter darting (used for large animals) Helicopter darting (used for large animals)
Sampling Wildlife There are many different kinds of capture methods, including: Aquatic dip nets (used in shallow water) Aquatic dip nets (used in shallow water) Mist nets (used for birds and bats) Mist nets (used for birds and bats) Helicopter darting (used for large animals) Helicopter darting (used for large animals) Live traps Live traps
Sampling Wildlife The marked individuals are released to mix with the rest of the population.
Sampling Wildlife Later, researchers capture a second sample. Some of the second sample will be marked and some will not.
Sampling Wildlife The total population N can be estimated using the Lincoln index formula: n1 = number captured the 1 st time n2 = number captured the 2 nd time m = number of marks found in the 2 nd sample
Sampling Wildlife For this to work: The time span between the 1 st and 2 nd samples must be short compared to the lifespan of the animal. The population must be closed: animals cannot immigrate (move in) or emigrate (move out).
Tracking Wildlife Some tags are numbered or contain radio transmitters and/or GPS receivers. These allow researchers to study animals’ movements.
Tracking Wildlife We can looking at tracking data on