The Kirtland's warbler (Dendroica kirtlandii) was among the first animals to gain federal protection in 1967 under the Endangered Species Preservation Act, The Kirtland’s warbler is a small songbird that nests in young jack pine forests in northern Michigan, Wisconsin and Ontario, Canada. It requires large stands of young, dense jack pine forest at least 80 acres in size, but prefers stands of 300 to 400 acres or larger. This warbler has one of the most geographically restricted breeding distributions of any bird in the U. S. The exact habitat it uses for nesting within jack pine forests is very specific and depends on disturbance, which historically was wildfire: they build their nests on the groundand the jack pines must be just the right height, 5 to 16 feet tall, and the trees must be spaced to let sunlight through to the ground. Sunlight helps keep lower tree branches alive and bushy, hiding the nest beneath them. After nesting and raising their young, Kirtland's warblers migrate to the Bahamas where they winter in scrub thickets. Primarily insect eaters, Kirtland’s warblers forage for insects and larvae near the ground and in lower parts of pines and oaks. Fires play an important role in forest ecosystems where the warbler lives. Without fire, jack pine cones do not completely release their seeds and suppressing forest fires prevents the natural establishment of new jack pine stands.

Question

The Kirtland's warbler (Dendroica kirtlandii) was among the first animals to gain federal protection in 1967 under the Endangered Species Preservation Act, The Kirtland’s warbler is a small songbird that nests in young jack pine forests in northern Michigan, Wisconsin and Ontario, Canada. It requires large stands of young, dense jack pine forest at least 80 acres in size, but prefers stands of 300 to 400 acres or larger. This warbler has one of the most geographically restricted breeding distributions of any bird in the U. S. The exact habitat it uses for nesting within jack pine forests is very specific and depends on disturbance, which historically was wildfire: they build their nests on the groundand the jack pines must be just the right height, 5 to 16 feet tall, and the trees must be spaced to let sunlight through to the ground. Sunlight helps keep lower tree branches alive and bushy, hiding the nest beneath them. After nesting and raising their young, Kirtland's warblers migrate to the Bahamas where they winter in scrub thickets. Primarily insect eaters, Kirtland’s warblers forage for insects and larvae near the ground and in lower parts of pines and oaks. Fires play an important role in forest ecosystems where the warbler lives. Without fire, jack pine cones do not completely release their seeds and suppressing forest fires prevents the natural establishment of new jack pine stands.

Question 1
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
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.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.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.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.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.

Answer 1

In this case, all of the options provided could apply as reasons for the decline in the number of Kirtland's warblers.

A. Fire removes plants that compete with jack pines for forest space, allowing for the creation of suitable nesting habitats for the warblers.
B. Fire suppression had allowed the jack pine forests to become too old for the birds to use as nesting sites, as they require young jack pine forests.
C. Fires effectively remove competing bird species in the area, reducing competition for resources for the Kirtland's warbler.
D. Kirtland's warblers nest in stands of young jack pines, and heat from wildfires is needed to open cones to release seeds and rejuvenate the young tree stands necessary for nesting.