White-winged and black terns are two similar species of small migratory birds in the tern family. While they share some characteristics, there are also key differences between these two types of terns in terms of their physical appearance, habitat, nesting behaviors, diet, and conservation status.
Quick Facts
White-Winged Tern
- Scientific Name: Chlidonias leucopterus
- Length: 8-10 inches
- Wingspan: 20-24 inches
- Plumage: Gray back and wings, white forehead and underparts, black cap on head
- Beak: Red with black tip
- Range: Africa, southern Europe, Asia, Indonesia, New Guinea
- Habitat: Marshes, lakes, rivers
- Diet: Small fish, insects, crustaceans
- Nesting: Colonial nester, floating nests in emergent vegetation
- Conservation: Least Concern
Black Tern
- Scientific Name: Chlidonias niger
- Length: 8-10 inches
- Wingspan: 20-23 inches
- Plumage: Gray back, white belly, black head and underparts
- Beak: Black
- Range: North America, southern Canada, northern South America
- Habitat: Marshes, lakes, rivers
- Diet: Small fish, insects, crustaceans
- Nesting: Colonial nester, floating nests in emergent vegetation
- Conservation: Least Concern
Physical Appearance
Though similar in size, white-winged and black terns can be distinguished from each other based on their plumage.
The white-winged tern has light grey upperparts and wings, with the exception of its namesake white feathers on the leading edge of its wings. Its forehead and underparts are white. It has a black cap on its head that does not extend below its eyes. Its slender bill is red with a black tip.
The black tern has dark grey upperparts and is darker overall than the white-winged tern. Its belly is white, but its head and underparts are fully black. Its bill is all black. Its wings do not have the white feathering of the white-winged tern.
When seeing these birds side by side, the plumage differences make them easy to tell apart. The black tern lives up to its common name with its dark hood and body, while the white-winged tern shows off its lightly colored wings in flight.
Geographic Range
White-winged and black terns have different geographic breeding and migration ranges.
White-winged terns have breeding grounds that extend from southern Europe through Africa and Asia. They migrate and overwinter in sub-Saharan Africa, India, and Indonesia.
Black terns breed mainly in North America, across central and eastern Canada and the northern United States. They migrate to wintering grounds extending from Mexico through northern South America.
There is some overlap between these two species. White-winged terns can be rare migrants or vagrants in North America, while black terns may show up infrequently in Western Europe. But for most part, white-winged terns frequent the Eastern Hemisphere while black terns are found in the Western Hemisphere. Their ranges only significantly overlap during migration periods.
Habitat
Both white-winged and black terns utilize similar wetland habitats. They are found predominantly near shallow freshwater lakes, ponds, marshes, and slow-moving rivers.
These terns frequent water bodies with abundant emergent vegetation, like reeds and cattails. They use these marshy areas for nesting and foraging habitat.
Occasionally white-winged and black terns may visit coastal marine habitats or estuaries during migration or winter. But their breeding sites are always located at inland freshwater marshes and wetlands.
Within these wetland ecosystems, their habitat preferences are essentially identical. The two tern species both thrive in areas with shallow, slow-moving water and plenty of floating vegetation for nesting.
Nesting and Reproduction
White-winged and black terns exhibit very similar nesting behaviors and preferences.
Both species nest in colonies, often alongside other marsh-nesting birds like coots or grebes. Their nests consist of floating platforms of vegetation anchored to emergent reeds or grasses in shallow water.
The terns lay 2-4 eggs in nests from late April to early July. Incubation lasts around 3 weeks, and chicks fledge in another 3-4 weeks after hatching.
Parental care duties are shared by both the male and female. The terns are fiercely defensive of their nests and young. They may dive-bomb or distract predators near their colonies.
The nesting chronology and parenting behaviors of white-winged and black terns are essentially identical. Their adaptations for colonial marsh nesting demonstrate their close evolutionary relationship as species.
Diet
White-winged and black terns are insectivorous birds that feed primarily on small fish, aquatic insects, and crustaceans.
From their foraging perches near nesting colonies, they scan for prey below the water’s surface. They plunge-dive to catch small fish and invertebrates in shallow marshes and lakes.
Both species are adept at hovering and diving for food. They may also flycatch emerging aquatic insects. Common prey includes minnows, damselflies, caddisflies, and other small marsh fauna.
Throughout the breeding season, the terns bring back food to regurgitate to their chicks in the nest. Their diet provides ample nutrition to support growth of the young.
In all regards, the dietary preferences of white-winged and black terns are virtually identical due to their similar ecology and foraging strategies.
Migration
White-winged and black terns undergo long annual migrations between their northern breeding areas and southern wintering grounds.
White-winged terns may migrate 5,000 miles or more each way between Europe/Asia and Africa. Some black terns also migrate huge distances between the northern U.S./Canada and South America.
These marathon migrations are fueled by the terns’ need to find optimal habitat and food resources during the breeding season. Their migrations trace broadly the same north-south pathways between continents annually.
Migrating flocks may mix with other tern species or shorebirds. The terns stop to rest and feed at wetlands along their migration routes.
Despite inhabiting different hemispheres, white-winged and black terns follow parallel migratory patterns and behaviors between continents. Their migrations allow range overlap in wintering areas.
Conservation Status
Of the two species, black terns face more significant conservation threats and declines.
White-winged terns are still abundant across their extensive Eurasian range. They are classified as Least Concern by the IUCN Red List. No major threats to the overall population have been identified.
Black terns, however, have declined more rapidly, especially in areas like the U.S. Midwest where wetlands have been widely drained and degraded. They are now listed as Near Threatened with ongoing population decreases from habitat loss.
Wetland conservation is important for supporting both tern species across their ranges. But black terns are more vulnerable currently due to steeper declines in their more restricted geographic range. Monitoring and management of black tern breeding habitat remains a focus for conservation.
Main Differences
Plumage
- White-winged tern has pale grey back, black cap, white forehead and underparts
- Black tern has dark grey back, fully black head and underparts, white belly
Range
- White-winged tern found in Africa, Europe, Asia
- Black tern found in North America, southern Canada, northern South America
Conservation
- White-winged tern is Least Concern
- Black tern is Near Threatened with decreasing populations
Conclusion
In summary, white-winged and black terns represent two closely related species that utilize similar wetland habitats and behaviors but live on separate continents. The black tern faces higher conservation threats currently, but protecting wetlands worldwide will benefit the future of both species. Their differences in plumage and range make identification straightforward, but their similarities reflect their near identical ecological niche. With focused management efforts, both these elegant marsh terns can continue thriving for generations to come.