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Fish for the Pufflings: Food and a Seabird Colony

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Fish for the Pufflings: Food and a Seabird Colony

Use six years of island records to explain how the fish supply affects puffin chicks and the colony.

Six years at the colony

Read the passage and Table 1, then answer the questions.

A Boat Trip to Kestrel Island

1In July, Ms. Rosalind Achebe's seventh-grade marine biology class took a boat from the harbor at Port Ellery to Kestrel Island, a rocky island in the Gulf of Maine. Hundreds of pairs of Atlantic puffins nest there each summer. The island's seabird biologist, Dr. Paavo Lindqvist, met the class at an observation blind, where student Adaora Mbeki asked him how the colony was doing.

2Dr. Lindqvist explained that each puffin pair lays a single egg in a burrow dug into the soil or tucked between rocks. After the chick, called a puffling, hatches, both parents fly out to sea to catch small fish. They return carrying several fish crosswise in their bills; each delivery is called a bill load. The puffling stays in the burrow and leaves for the sea when it is about six weeks old. At Kestrel Island, the most common fish in bill loads are sand lance, thin silver fish that school in shallow water and burrow into the sandy seafloor.

3Every July, the island team counts the burrows with an egg, watches marked burrows to count bill loads, weighs chicks when they are 30 days old, and records which burrows raise a chick that leaves for the sea, or fledges. A research boat also tows a net through the waters around the island to count sand lance. Gulls nest on the island too, and their numbers stayed about the same in every year of the study. Table 1 shows six years of records.

4Dr. Lindqvist added that band records from many seabird colonies suggest that chicks that leave the nest heavier are more likely to survive their first winter at sea. Young puffins usually do not come back to breed until they are about five years old. Adult puffins often live for 20 years or more, so a colony can usually get through a single poor year, but several poor years close together can make it shrink.

Table 1. Kestrel Island Puffin Records (July averages)
Year	Sand lance per haul	Bill loads/chick/day	Chick mass, day 30 (g)	Burrows with an egg	Fledged per 100 burrows
2019	120	8	290	400	72
2020	105	7	280	420	68
2021	40	4	215	380	33
2022	30	3	200	400	25
2023	90	7	270	390	62
2024	130	8	295	430	75

1.

Chicks fledged = burrows with an egg × (fledged per 100 burrows ÷ 100).

About chicks fledged on Kestrel Island in 2019, and about chicks fledged in 2022.

2.

Which pattern does Table 1 show?

A. Years with fewer sand lance had fewer bill loads, lighter chicks and fewer chicks fledging.B. Years with more bill loads had lighter chicks, because the chicks spent more energy eating.C. Years with fewer sand lance had fewer burrows with an egg, so fewer chicks fledged.D. Chick mass at 30 days fell a little in each year from 2019 to 2024.

3.

Use the passage and Table 1. What most likely limited the number of chicks that fledged in 2021 and 2022?

A. Food, because sand lance were scarce and parents brought fewer bill loadsB. Nesting space, because no more burrows were free on the island in those yearsC. Eggs, because pairs laid two eggs in good years and one egg in those yearsD. Gulls, because more gulls nested on the island and took chicks in those years

4.

Which pair of years best shows that the number of chicks fledged depended on the food supply, not on the number of pairs nesting?

A. 2021 and 2022B. 2019 and 2022C. 2019 and 2024D. 2020 and 2023

5.

In July 2025, the net survey finds about 70 sand lance per haul, and about 400 burrows have an egg. Based on Table 1, which result is most likely?

A. More than 75 chicks fledged per 100 burrows, a new highB. About 20 chicks fledged per 100 burrows, fewer than in 2022C. Between 33 and 62 chicks fledged per 100 burrowsD. About 75 chicks fledged per 100 burrows, as in 2024

Chick by chick

The team weighed 20 marked chicks at 30 days old in a good year and 20 marked chicks in a poor year. Use the two histograms.

2020: masses of 20 chicks at 30 days old

2022: masses of 20 chicks at 30 days old

6.

Count the chicks that weighed less than 240 g. In 2020 there were such chicks, and in 2022 there were .

7.

Which statement compares the two histograms best?

A. In 2022, the chicks fell in the same mass groups as in 2020, but fewer chicks were weighed.B. In 2022, most chicks weighed from 280 to 320 g, the same group as most chicks in 2020.C. In 2022, a few chicks were heavier than any chick in 2020, which raised that year's average.D. In 2022, most chicks weighed less than 240 g, while in 2020 most weighed 240 g or more.

8.

Dr. Lindqvist claims that in 2022 the parents could not find enough fish. Circle the two results that most directly support this claim.

The colony in the years ahead

9.

Use paragraph 4 and the data. Which change is most likely at the colony in 2026 and 2027?

A. A larger colony, because chicks that leave light catch up in growth once they reach the seaB. Fewer young adults joining, because few chicks fledged in 2021 and 2022 and many were lightC. More burrows with an egg, because the 2021 and 2022 chicks will need burrows as adultsD. Many more young adults joining the colony, because the 2024 chicks will be old enough to breed

10.

A visitor on the boat says, “The colony raised fewer chicks in 2022 because fewer puffin pairs came back to nest that year.” Do you agree? Write a claim, use evidence from Table 1 and the histograms, and explain how the amount of food affected individual chicks and the colony.