Conservation and Management

In the mid-1800s, skimmers were persecuted like most other colonial waterbirds, through egging and market hunting of adults. Egging (including commercial egging) by humans was of great historical importance in diminishing skimmer populations; population size was described in terms of numbers of bushels of eggs collected (Bent 1921, Stone 1937).

Currently, human disturbance and intrusion are major factors affecting skimmer colonies (Schreiber and Schreiber 1978). Non-habituated colonies can be seriously disturbed by human intruders (Bales 1919), and birds return to nest slowly, even when the intruder is in a blind. Erwin (1980) showed that pre-laying skimmers may abandon a colony that is frequently disturbed. Experimentally disturbed subcolonies had lower nest density, later nesting, and lower hatching and fledging success; disturbed chicks occasionally ate younger conspecifics. Fencing of nests lowers fledging success in undisturbed subcolonies but raises success in frequently disturbed areas (Safina and Burger 1983). Incubating skimmers more tolerant of intrusion, but field studies that frequently disturb nesting areas after hatching lead to earlier dispersal of skimmer families. At some barrier beach island colonies, off-road vehicles (ORVs) are a major threat, requiring total beach closure for the entire breeding season. Vandalism—deliberate destruction of eggs and chicks and shooting of adult skimmers—has been a problem in certain areas (e.g., Long Island, NY) (Burger and Gochfeld 1990). Skimmers and terns habituate to noise, but early in the season groups show frequent upflights when airplanes detected (Burger and Gochfeld 1990). In the 1990s, collecting of eggs for food by people of Asian descent is an increasing problem for colonial seabirds.

Status varies from Endangered (e.g., New Jersey) or Threatened (e.g., New York) to Special Concern (e.g., N. Carolina, Florida). Loss of breeding habitat is the main factor affecting status.

Protection of suitable breeding colony sites is essential and represents an ongoing problem in the face of expanding human populations and their attraction to the coastal beaches and islands required by skimmers. At least for the eastern population(s), management is facilitated because a significant portion of the population winters in the U.S. The species is protected by international treaties, but the degree of exploitation on wintering grounds in Mexico and Central America should be examined. Although skimmers shift colony sites (see Demography and Populations), large colonies tend to be stable for more than a decade and can be protected by preventing development, restricting ORVs, fencing, and educational sign posting. Wardening to prevent egging and to keep dogs out is important. Skimmer colonies are readily detected from the air, and an aerial survey early in the breeding season can provide an estimate of breeding numbers and of sites needing protection; probably little need to protect sites with < 10–20 pairs since such small groups are likely to shift in subsequent years.

Because skimmers nest (and roost) in open areas, they are well-suited to public viewing from a blind at the edge of the colony—an education opportunity. In colonies on disturbed beaches, fenced corridors between subcolonies help keep people from entering the nesting areas; skimmers are likely to habituate to passersby.

Research is needed to determine whether foraging habitat is threatened and the role of food-chain amplification of pollutants. At present, data suggest that pollutants are not having a major impact on populations (see Demography and Populations: causes of mortality). Because skimmers do not land on water, they have some protection from oil spills, but oil spills in their preferred feeding habitat adjacent to shipping channels do occur and could have major impacts.

Ideally skimmer populations should be monitored annually in each state; monitoring at intervals > every 3 yr is inadequate. There has been a dramatic decrease in monitoring of waterbird populations since the early 1970s and this trend should be reversed.

Banding of young skimmers is potentially very disturbing, causing them to run long distances and decreasing survival (Safina and Burger 1983), nevertheless, judicious use of banding within a controlled research protocol is needed to document colony movements, recruitment, survival, and age-specific fecundity. The quality and quantity of fish stocks should be monitored and protected.