Nests:
- nest in colonies
- place nests on the ground in bare sand
- lay 2 - 3 eggs in a small cup-like depression
- produce one per season
- may re-nest up to three times if the nest is lost early in the season
- do not nest until their 3rd summer
- can live 20 years or more (record is 24 years)
Eggs:
- Well camouflaged (pale to tan with dark spots but coloration is highly variable)
- Take about 21 days to hatch
- A little larger than a quarter
Chicks:
- Coloration varies from grayish-brown to yellow to nearly reddish or sandy-brown with white undersides and tiny dark spots on head and back
- Semiprecocial which describes young that have open eyes, down, and are mobile at hatch but don't leave the nest right after hatching
- Typically leave the nest within two days of hatching
- Flightless and depend on parents for food (small fish) and protection until about 21 days
Defensive Behavior
- Adults are aggressive
- Adults defend nest and chicks by mobbing, dive bombing, and defecating on intruders
- Chicks will usually lay flat on the sand pretending to be a rock or they will hide under a plant, rock, or piece of driftwood
Nest and Chick Predators:
- American Kestrels (Falco sparverius)
- Great Blue Herons (Ardea herodias)
- American Crows (Corvus brachyrhynchos)
- Owls
- Skunks
- Raccoons
- Foxes
- Coyotes
- Cats
- Dogs
- Humans
Interior Least Tern nest on a river sandbar 
Three Interior Least Tern eggs 
Nest with newly hatched chick 
Nest with 2 eggs 
Two day old tern chicks in nest cup 
Tern chick resting on the sand 
12-day-old chick being weighed 
Newly hatched tern chick 
Chicks being feed fish 
2-day-old chick with leg band 
3-day-old chicks under a plant 
7-day-old chick hiding 
Chick with yellow-green leg band 
Fledgling tern 
Tern chick hiding in the vegetation 
Adult dive bombing intruders 
Chick pretending to be a rock
