The Central Nebraska Public Power and Irrigation District
Least Terns & Piping Plovers in Nebraska
Introduction
The Interior Least Tern, smallest member of the gull family, and the Piping Plover, one of the smallest members of the plover family, are two species of birds that share the beaches of Lake McConaughy and sand bars of the Platte River system in Nebraska with a growing number of hikers, campers and other outdoor enthusiasts. They are also threatened with extinction.
Both species nest along the 76 miles of wide, sandy beaches at Nebraska’s largest reservoir, Lake McConaughy. While populations have declined over much of the birds’ ranges, their numbers at Lake McConaughy are steady or increasing. Their numbers are greatest at Lake McConaughy when the lake is less than full; exposing wide beaches that are ideal for nesting. This is also the time when the greatest recreational use of the shoreline occurs.
To ensure that these two species have the chance to recover and thrive in Nebraska, efforts are underway to understand the habitat needs of these species. It is recognized that public education provides the most effective and positive impact upon these two species — indeed, upon all wildlife in Nebraska.
Least Tern (Sterna antillarum)
The least tern is a pale gray-white bird with black outer wing feathers and yellow legs and bill. The tail is slightly forked and the head has a black cap over a white forehead with black eye stripes.
Terns fly with rapid wing beats and often hover. While searching the water surface for prey, the bird will suddenly plunge into the water to capture small fish, thus the nickname “Little Striker.” Although it dives into the water for fish, the tern rarely swims, while its close relatives, seagulls, swim but rarely dive.
Immature (less than one year old) least terns have white heads and underbodies with brownish backs and upper wings. The fork in the tail is less evident than that of the adult. Immature terns may be seen flying the beaches of Lake McConaughy during late July and early August before migrating to wintering grounds along the coast of Latin America.
Piping Plover (Charadrius melodus)
The piping plover is a small sand-colored bird with a white breast and a single dark ring around the throat. Smaller than a robin, the piping plover has orange legs and an orange bill with a black tip. The piping plover is often confused with the slightly larger killdeer, which is distinguished by the two dark rings around its throat and its strident “killdeer” call. Piping plovers are difficult to see against the gravel and sand of the beach, so often the easiest way to locate the bird is by its plaintiff “peep-lo” whistle.
Another way to identify the plover is by its “broken-wing” act. The birds perform the act to draw intruders away from their chicks or eggs. With one wing outstretched, the parent plover will hobble away from its nest as though injured, presenting the appearance of easy prey to a predator. However, as the intruder nears, the plover suddenly “recovers” and escapes.
Piping plovers feed on invertebrates found in the moist sand along the shore.
Nesting
Both the least tern and the piping plover nest in shallow scrapes in the sand, laying tan, speckled eggs in the nest. Terns typically lay up to three eggs and plovers up to four eggs. The two species often share the same nesting areas.
While the piping plover usually nests singly, least terns typically nest in colonies. Adult terns will protect the area by diving at intruders and dropping excrement on those that get too close to the nests.
Both birds are opportunistic nest-builders, which enables them to respond to changes in habitat. The birds typically return to the same area each year, but if the habitat has changed, they will shift to other areas. If their nests are destroyed or disturbed early in the nesting season, the birds will usually relocate and re-nest. Piping plover eggs are normally laid in early to mid-May and least terns nest from late May to early June. However, nesting may extend into midsummer for both species if the original nests are destroyed.
Least terns incubate their eggs for about three weeks. The young are able to run quite well within a few days after hatching. After about three weeks, the young fledge — that is, they grow flight feathers and begin learning to fly. However, they are still fed and protected by the parents until migration.
Piping plovers incubate eggs for about four weeks. The young birds are precocial (covered with down and fully active when hatched) and are able to run and feed themselves within several hours of hatching. Plover chicks fledge at about four weeks.
Terns and plovers have life spans of about ten years, which helps the species offset the occasional years of low productivity.
Threats to Nesting Success
Presently, investigators are trying to determine the causes for these birds’ threatened existence throughout North America. Early evidence seems to indicate that while habitat has been declining in some areas of the northern Great Plains, there is still unused nesting habitat available in Nebraska. Both species will make use of river sandbars and spoil piles at sand and gravel operations, as well as the beaches of lakes and reservoirs. In addition, man-made islands have been established in the Platte River for use by terns and plovers (although chick production on these islands has been irregular so far and the birds show no preference for sandpits, beach or islands). While additional research is necessary, predation, flooding caused by rainfall, and — at some locations — human disturbance are the major causes of nest and chick loss in Nebraska.
Of these threats, human disturbance is the more manageable problem. Lake McConaughy and the Platte River are, and have been for many years, sites for a variety of recreational activities. Unfortunately, the areas that people use for recreation are often the same areas used by terns and plovers for nesting.
Of particular concern is the use of off-road recreational vehicles. The speed at which these vehicles travel and the amount of area which they can cover increases the danger of disturbing or destroying tern and plover nests, eggs and chicks.
To prevent the destruction of nesting sites at Lake McConaughy, off-river sandpits and riverine sandbars, known nesting areas are marked with signs to alert the public to the presence of nests. Additionally, specific areas at Lake McConaughy are reserved for these species. Signs alerting beach users to the birds’ presence are posted throughout the recreation area and other areas are fenced off.
It is impossible to mark all of the nesting sites, but regardless of whether or not the areas are marked with signs, disturbance of an endangered species is a violation of state and federal laws and is punishable by a jail sentence and forfeiture of any vehicles used in disturbing a nest. The best action to take upon discovering a nest site is to avoid it completely.
The Future
Optimum conditions for tern and plover nesting come and go. Production of terns and plovers in Nebraska varies considerably from year to year depending upon the location. This is a natural occurrence because of the often unforgiving nature of Nebraska’s weather — floods, heat, wind, hail — as well as the impact of predators and people. But today, despite the many dangers facing the birds, their future is brighter. With continued research and habitat protection and restoration (as Central has done at Lake McConaughy and sites along the Platte River) and with work being done by other utilities and private conservation groups, progress is being made toward securing a future for these birds.
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