This is an egg from the Whiskered Tern (Chlidonias hybrida), a medium‑sized marsh tern belonging to the family Laridae (terns and gulls).

Adult Whiskered Terns measure approximately 24–28 cm in length, with an average weight of about 80 g. In breeding plumage the head is black with white cheeks and sides of neck, the upperparts (back, shoulders and rump—the top side of the bird) medium grey, underparts (belly and chest) somewhat darker, and the bill and legs red. Outside the breeding season the cap becomes paler or streaked, the forehead whitish, and bill and legs darker. Juveniles have a mottled brownish‑grey back and paler underparts. The tail is shallowly forked, and the rump remains pale grey in most plumages. The call is a hoarse “kerch / kerrrk”.

Location:
The Whiskered Tern breeds in wetlands across southern Europe, much of Asia including the Indian Subcontinent, south‑eastern Africa, Madagascar and Australia. Many populations migrate or are nomadic, moving according to seasonal wetland conditions. Habitats include inland freshwater wetlands such as marshes, flood‑plains, large dams, irrigated cropland and also brackish or saline lakes; nests are typically sited over or beside water on floating or emergent vegetation.

Average Size:
Length: ~24–28 cm. Weight: ~80 g.

Family:
Laridae (terns and gulls)

Species:
Chlidonias hybrida

Ecological Role:
Feeds on small fish, aquatic amphibians, crustaceans and insects by dipping, skimming or shallow plunging over water. Breeding colonies provide structural habitat for other wetland species by their raft‑style nests and dense aggregations; the terns also defend their nests aggressively, which can benefit other species nesting nearby.

Movement and Behaviour:
Many populations are migratory or nomadic, moving between wetlands as water availability changes. Breeding colonies form rapidly when conditions are appropriate, often on shallow, temporary wetlands. Within colonies the birds may swarm or mob predators or intruders in aerial displays and calls.

Reproduction & Eggs:
Nests are built on floating or emergent vegetation platforms in shallow wetlands. Clutch size is typically 2–3 eggs. The eggs are generally greenish, sometimes green‑blue, blotched or speckled with brown or olive markings, providing camouflage against floating nest vegetation. Incubation is shared by both sexes and lasts about 20–22 days. Hatching is often asynchronous, and chicks fledge about 20–27 days after hatching, depending on conditions.

Conservation Status:
Globally assessed as Least Concern. Local populations may be vulnerable to habitat degradation, wetland drainage, unstable water levels and disturbance at breeding sites.

Collection Date:
This specimen was collected in South Russia in May of 1900.