Lecture October 31 – Habitat Selection (cont’d)

The American redstart
Aggression is a phenotype
If some birds are more aggressive, they can use this as an advantage to monopolize the higher quality habitat
Graph: choice of region (red line  Black mangrove forest (preferred); green line  second-growth scrub) for over-wintering grounds.
Those that are in the prime habitat get to depart earlier because they are in better shape to fly back home.

Data of the same species based on where they over-wintered.
When they get back
There is a marked decline in number of young fledged for both males and females who over-wintered in the less desirable region.
Females declines even faster; possible reasons  the females generally invest more energy on ones fledge.
Male can have more than one partner, hence more chance of fledged young. Extra-pair copulations.

Video showing fierce combat between butterflies. Sunny patches are more valuable to the males.
This will go on until the resident male chases off the intruder.

Typically the resident male wins, then goes back to the perch.
Residential status has an advantage.
This study may have been flawed
i.e. catching the white butterfly would have cause it physical stress.
Resource-holding power: they are able to keep their resource in the face of challenge.

Bright coloured pigments are difficult to reproduce (red-shouldered widowbird)
Only the hard-do beat individuals have honest signals (i.e.