Read paragraph 2 and think about how the key details provide evidence or an explanation of the central idea in the text.

Paragraph 2:

The passenger pigeon (Ectopistes migratorius), once numbering in the billions, was thought by some to account for one quarter of all land birds in North America. Such astonishing numbers are hard to imagine today. The birds aggregated in flocks comprising hundreds of millions of individuals. Eyewitnesses described migrating flocks that stretched a mile wide, darkening the sky for days with their grayish-brown bodies as they flew overhead. The sound of millions of wings beating in unison was said to be deafening, as loud as a freight train passing overhead. The down draft of their wings would cool the air below. The renowned painter and naturalist, John James Audubon, recorded a pigeon flight along the Ohio River in 1813 that eclipsed the sun for three days.

Key Details

• once numbering in the billions
• aggregated in flocks comprising hundreds of millions of individuals
• darkening the sky for days
• beating in unison was said to be deafening
• a pigeon flight along the Ohio River in 1813 eclipsed the sun for three days

Considering these details, which statement best represents the central idea of paragraph 2?

Read the next paragraph and think about how the key details provide evidence or an explanation of the central idea in the text.

Paragraph 3:

When the birds finally arrived at their destinations, they would take over entire forests. Roosting in such large numbers, they would destroy the trees on which they gathered. Observers reported that the sheer weight of so many birds would cause the trees to bend until their tops touched the ground, their branches snapping off, and their trunks uprooting. The devastation was likened to a tornado or hurricane blowing through the forest.

Key Details

• take over entire forests
• destroy the trees on which they gathered
• branches snapping off, and their trunks uprooting
• the devastation likened to a tornado or hurricane

Considering these details from paragraph 3, which statement best represents the central idea of the article so far?

Read the next paragraph to determine the key details on your own. Refer to the Glossary in the top right corner of the page for definitions of words in boldface.

Paragraph 4

The species was hunted in overwhelming numbers because the birds could be shot or netted in such huge numbers to satisfy the demand for their tasty meat. The deforestation of land destroyed its habitat, and infectious diseases spread through the colonies. A gregarious species, the passenger pigeon could not survive when the flocks began to dwindle, and within a generation or two, the species had vanished. It is unfathomable how such an abundant species could be driven to extinction within such a short timeframe. Another species lost. A new normal established. Future generations would only know this bird through historical accounts.

Which of the following statements best represents key details from this paragraph? Select ALL that apply.

Considering the details from paragraph 4, which statement best represents the central idea of the article so far?

Read paragraph 5.

Paragraph 5:

The passenger pigeon's plight is not unique. Nearly a half-century earlier, the great auk (Pinguinus impennis), a flightless seabird known to North Atlantic shores, was lost. The Carolina parakeet (Conuropsis carolinensis) no longer travelled in noisy flocks from southern New York and Wisconsin to the Gulf of Mexico after 1918. And by 1932, the heath hen (Tympanuchus cupido cupido) disappeared from its open prairie habitat in the Northeast. These once common species began to steadily decline in the 1600s as a result of over-hunting, habitat loss, and introduced predators. Each event is testament to the fact that even the most abundant species can be rendered extinct.

Considering what you have read so far, what one central idea do the most important key details support?