GMAT Reading Comprehension Practice Set # 2

1. What is thought to be the primary cause of the population decline of the ferruginous pygmy owl in the Rio Grande Valley?

The Texas population spontaneously migrated to Arizona.

Destruction of the Rio Grande River Valley.

Brush clearing between 1920 and 1945 destroyed the birds' habitat.

Land development between 1990 and 1995.

Failure of the U.S. Fish and Wildlife Service to add the bird to the Endangered Species list.

From the text: "Extensive brush clearing between 1920 and 1945 may have caused the decline of this species (Oberholser 1974)."

Explanation

From the text: "Extensive brush clearing between 1920 and 1945 may have caused the decline of this species (Oberholser 1974)."

2. According to the passage, why did the US Fish and Wildlife service want to count nocturnal birds in this study?

No one had endeavored to count nocturnal birds before.

To account for unknown species of birds found in the 1997 count.

To complete the species checklist for the Galvan Ranch.

To verify the existence of 28 tropical species in the 1997 count.

To account for all known migratory species absent in the 1997 count.

From the text: "To complete the species checklist for this ranch, the U.S. Fish and Wildlife Service funded additional surveys of nocturnal birds on the Galvan Ranch in 1998."

Explanation

From the text: "To complete the species checklist for this ranch, the U.S. Fish and Wildlife Service funded additional surveys of nocturnal birds on the Galvan Ranch in 1998."

3. What is the significance of the 1997 Galvan Ranch study?

It was the first survey of breeding and migratory birds in the Lower Rio Grande Valley area.

It demonstrated that tropical species were fleeing their natural habitats.

It demonstrated that most of the species living in southern Texas were native to the area.

It proved that the ferruginous pygmy owl was still living in Texas.

From the passage: "In 1997, breeding bird surveys conducted by Woodin et al. (1998) on the Galvan Ranch (located along the Rio Grande northwest of Laredo) represented possibly the first scientific survey of breeding and migrating birds within this region of Texas."

Explanation

From the passage: "In 1997, breeding bird surveys conducted by Woodin et al. (1998) on the Galvan Ranch (located along the Rio Grande northwest of Laredo) represented possibly the first scientific survey of breeding and migrating birds within this region of Texas."

4. What is the most likely explanation for the number of tropical species on the Galvan Ranch?

Tropical birds are being forced from their natural habitat due to the destruction of the rainforests.

The Lower Rio Grande Valley is part of the birds' migratory pattern.

Overpopulation of the tropical species in their natural habitat has forced the bird to migrate northward.

The tropical species were misidentified.

The birds were carried to the area as "stowaways" on commercial transport vehicles.

From the text: "Several of the tropical species had been thought to exist in the U.S., only in the Lower Rio Grande Valley."

Explanation

From the text: "Several of the tropical species had been thought to exist in the U.S., only in the Lower Rio Grande Valley."

5. Between the years of 1990 and 1995, annual bird surveys in Arizona showed that the population of ferruginous pygmy owls:

Remained constant.

Was negligible.

Grew from less than three to 16.

Migrated to Texas.

Disappeared altogether.

From the text: "In Arizona, however, where the only other population of ferruginous pygmy-owls in the United States exists, the bird is very scarce. Between the years 1990 and 1995, annual surveys conducted by the U.S. Fish and Wildlife Service, the U.S. National Park Service, and the Arizona Fish and Game Department resulted in ? 3 individuals per year."

Explanation

From the text: "In Arizona, however, where the only other population of ferruginous pygmy-owls in the United States exists, the bird is very scarce. Between the years 1990 and 1995, annual surveys conducted by the U.S. Fish and Wildlife Service, the U.S. National Park Service, and the Arizona Fish and Game Department resulted in ? 3 individuals per year."

6. In the passage, the author describes the ferruginous pygmy owl as a "common resident in the riparian woodlands and dense brushland of the lower Rio Grande Valley..." From this statement, what can you infer about the Texas population versus the Arizona population of the pygmy owl?

The pygmy owl must have migrated to Arizona when its habitat was cleared.

The pygmy owl preferred Texas.

The pygmy owl's habitat includes northern Mexico.

The pygmy owl's probability of survival is higher in the woods than in the desert.

The pygmy owl may have originated in the tropics.

If the species was common along waterways and in dense brush, the population must have done well in that habitat. In contrast, the Arizona population was extremely small, suggesting that the population was having difficulty surviving in the Arizona environment. Based on the number of individuals counted in each region, the reader can conclude that the bird is better suited to the Texas environment.

Explanation

If the species was common along waterways and in dense brush, the population must have done well in that habitat. In contrast, the Arizona population was extremely small, suggesting that the population was having difficulty surviving in the Arizona environment. Based on the number of individuals counted in each region, the reader can conclude that the bird is better suited to the Texas environment.

7. What is the most likely reason the US Fish and Wildlife Service was interested in the population of ferruginous pygmy owls in the 1998 study?

To see if the Texas and Arizona populations had combined.

To count the increase in the bird population.

To determine whether the pygmy owl is migratory.

To determine whether the species requires Federal protection.

To learn more about its nocturnal habits.

From the text: "Prior to 1989, only a few known pygmy-owls remained along the Rio Grande in Starr and Hidalgo Counties." Given that the number of pygmy owls was in decline, the Fish and Wildlife Service wanted to know how many owls were left to determine whether they were endangered.

Explanation

From the text: "Prior to 1989, only a few known pygmy-owls remained along the Rio Grande in Starr and Hidalgo Counties." Given that the number of pygmy owls was in decline, the Fish and Wildlife Service wanted to know how many owls were left to determine whether they were endangered.

8. In 1997, the U.S. Fish and Wildlife Service added the Arizona population of the ferruginous pygmy-owl to the Endangered Species List. Based on the passage, why was the Texas population left off the list?

Clerical error on the part of the U.S. Fish and Wildlife Service.

The ferruginous pygmy-owl was not known to exist in Texas after 1989.

The species was abundant throughout the Lower Rio Grande Valley.

The population had spread to Texas counties where the bird had not previously been counted.

"This species was considered in 1993 for federal protection under the Endangered Species Act. However, because of the difference in status between the Texas and Arizona populations, the U.S. Fish and Wildlife Service in 1997 listed only the Arizona population of the cactus ferruginous pygmy-owl (Glaucidium brasilianum cactorum) as endangered."

Explanation

"This species was considered in 1993 for federal protection under the Endangered Species Act. However, because of the difference in status between the Texas and Arizona populations, the U.S. Fish and Wildlife Service in 1997 listed only the Arizona population of the cactus ferruginous pygmy-owl (Glaucidium brasilianum cactorum) as endangered."