ถ่ายภาพ : ประสิทธิ์ จันเสรีกร

ภาคที่พบนกชนิดนี้

Identification Tips:

• Length: 14 inches Wingspan: 31 inches
• Sexes similar
• Dives into water for prey
• Medium-sized tern with slender, pointed bill
• Long, deeply forked tail
• Smoothly rounded head without crest
• Pale underwing with broad, blurry, dark trailing edge
• Gray upperwing with dark outer primaries (variable according to state of condition of plumage)
• Window of translucent primaries shows through wings on inner primaries and outer secondaries
• Alaskan birds can have all dark bills and brown legs
• Can take three years to reach full adult plumage

Adult alternate:

• Red legs
• Orange-red bill with black tip
• Black cap
• White face
• Medium gray foreneck, breast, and belly
• Gray back and upperwings
• Dark wedge in outer primaries
• Primary pattern darkens with wear through season so that outer 5 primaries are entirely dark by late summer
• White rump and tail, with dark edges to outer retricies
• Tail extends only to tip of primaries at rest

Adult basic:

• Red legs
• Black bill
• White forehead, face, foreneck, breast, and belly
• Black cap extends up from eye to crown and rearward from eye to back of head
• Outer primaries and tail feathers darken with wear, becoming dark gray in basic plumage
• Dark carpal bar

Juvenile:

• Pale flesh-colored legs
• Pink to yellow-based bill turning to black with age
• White forehead, foreneck, breast, and belly
• Back color variable-often gray with pale brown and black feather edges
• Dark carpal bar
• Gray wings with brown tips to the upperwing coverts
• Dark secondaries and lesser coverts contrast with paler inner wing
• Short tail with dark tips

Immature:

• First-year birds like adult basic
• Second year birds like adult alternate, but often with white feathers in cap, paler breasts and faint carpal bars.