Forster's Tern: a two-minute wildlife lesson

At the Seaside · day 4 of 7

Five facts

1. When a predator nears a Forster's tern nest, the whole colony mobs it: adults dive at the threat with loud calls.
2. Yellow-headed blackbirds sometimes join the terns' attacks, and western grebes even recognise the tern's alarm call.
3. In crowded colonies, some terns nest on sand, gravel or mud, often lining the nest with driftwood, shells or dried fish.
4. Both parents care for the nest: males usually guard it by day, while females are there more at night.
5. Chicks can leave the nest by day four, but depend on their parents for food until they fledge at 28 days.

The quiz

1. What does the colony do when a predator approaches?

• Mobs it, diving with loud calls (correct)
• Hides silently
• Flies far away
• Buries the eggs

The whole colony mobs the predator with loud calls.

2. Which bird recognises the Forster's tern's alarm call?

• Bald eagles
• Western grebes (correct)
• Emperor penguins
• Snowy owls

Western grebes recognise the tern's alarm call.

3. What can these terns line their nests with?

• Moss and feathers
• Driftwood, shells or dried fish (correct)
• Mud and grass
• Leaves and fur

In crowded colonies they may nest on sand, gravel or mud, lined with driftwood, shells or dried fish.

4. Who guards the nest by day?

• The females
• Neither parent
• The males (correct)
• Other colony members

Males guard the nest more by day, females more at night.

5. At what age do chicks fledge?

• 4 days
• 10 days
• 60 days
• 28 days (correct)

Chicks depend on their parents for food until they fledge at 28 days.

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