22 NCEA Style Question: Migration

Sooty shearwater

The sooty shearwater (Puffinus griseus, muttonbird or titi) migrates up to 65,000 km. It is one of the longest migrations of any animal. From October to March, sooty shearwaters raise their chicks (which takes about 100 days) on oceanic islands around the sub-Antarctic region of New Zealand. During the breeding season, tens of thousands of chicks are taken by commercial hunters. From April to May, they begin migrating to specific areas of the sub-Arctic, arriving from June to July for the Northern Hemisphere summer. The sooty shearwater is often seen behind fishing trawlers picking up scraps.

1. Discuss the migratory behaviour of the sooty shearwater as it travels from sub-Antarctic waters to sub-Arctic waters (you may use extra paper if needed).

• Explain why it would undertake such a long migration • Explain some of the methods it may be using to navigate • Suggest reasons why its numbers have been dropping

2. Suggest why the sooty shearwater begins its return journey in October when North Pacific Ocean productivity is greater than South Pacific Ocean productivity.

Flight of two sooty shearwaters Position of birds vs ocean productivity Trade winds of Pacific Ocean

Latitude

60 40 20 0

-20 -40

-60 Position of birds North Pacific

Breed South Pacific

Migration Breed 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1

J FM M SONDJ JJA A Month (g C m -2

d-1 ) Productivity of oceans