Passenger pigeons once     1     (fly) over much of the United States in unbelievable numbers. Written     2     (account) from the 18th and 19th centuries described flocks (群)so large that they the sky for hours.

It     3     (calculate) that when its population reached its     4     (high) point, they were more than 3 billlion passenger pigeons—a number equal to 24 to 40 percent of     5     total bird population in the United States, making it     6     (true) the most abundant bird in the world. However, the population decreased because of     7     (commerce) hunters who killed them by the thousands. Americans' need for wood scattered the flocks and forced the birds to go farther north,     8     cold temperatures and spring storms contributed to their decline.

In 1897, the state of Michigan passed a law prohibiting the killing of passenger pigeons, only     9     (find) that by then, no sizable flocks had been seen in the state for 10 years. The last of them, known affectionately     10     Martha, died at the Cincinnati Zoological Garden on September 1, 1914.

More than 1,000 elephants face     1     (starve) in Thailand because of the coronavirus crisis. An almost total absence of visitors     2     (mean) that many caretakers are struggling to afford food for Thailand’s 4,000 captive elephants. The animals can eat up     3     200kg of food a day.

Lek Chailert,     4     (found) of the Save Elephant Foundation, told the BBC: “If there is no support     5     (keep) them safe, these elephants, some of whom are pregnant, will     6     starve to death or maybe put on to the streets to beg.” Some elephants maybe sold to zoos or they may     7     (return) to the illegal logging business, which     8     (official) banned the use of elephants in 1989.

“It’s very     9     (hope) until some financial help is received immediately,” Lek Chailert adds. It’s a challenge to keep the animals fed and healthy at     10     best of times but now it’s the dry season, which makes the situation even worse.