The drastic decline in the number of Kirkland's warblers, prompting the U. S. Forest Service to include the Kirtland’s warbler on the list of endangered species in 1967 under the Endangered Species Preservation Act of 1966 was due to
Responses
A. eggshell thinning due to DDT use.
B. habitat loss as young Jack pine forests matured.
C. competition for food among the other northern bird species.
D. the increase in wildfires that destroyed the developing Jack pine forests.
The U. S. Forest Service notes that the fire suppression policies of the last century were as damaging to the Kirkland's warbler population as DDT was to the bald eagle. How can extinguishing a wildfire be a listing factor to this bird's populations? All BUT ONE could apply.
Responses
A. Fire removes plants that compete with jack pines for forest space.
B. Fire suppression had allowed the jack pine forests to become too old for the birds to use as nesting sites.
C. Fires effectively remove competing bird species the area. Without periodic wildfires, Kirkland's warbler is outcompeted for food.
D. Kirkland’s warblers nest in stands of young jack pines. Heat from the wildfires is needed to open cones to release seeds to keep rejuvenating young tree stands.