Western Grebe
Low breeding numbers and threats to their nesting colonies put these birds at risk.
Ministry of Environment, Lands and Parks – in Salmon Arm Bay on Shuswap Lake, early 1940s, no nesting has occurred and in the north arm of Okanagan Lake since about 1964. At Swan Lake, where – are located in areas where recreational about 40 pairs nested between 1950 activity is already high and development and 1966, there has been no evidence of Why are Western Grebes could potentially increase. The Salmon nesting since 1992. Breeding colonies of at risk? Arm colony is also at risk from the up to 90 pairs at Shuswap Lake, 40 pairs he Western Grebe, a large waterbird impacts of cattle grazing along the lake at Okanagan Lake and 55 pairs at that breeds in the interior of British shore. The third remaining colony, at CVWMA have persisted in recent years. Columbia and winters on the coast, is the Creston Valley Wildlife Management Scattered occurrences of one or two nests T at risk in this province because its spe- Area (CVWMA), is less susceptible to at other locations have also been report- cialized habitat requirements limit it to human disturbance. Nevertheless, this ed. Although a few small colonies may only a few nesting locations and because of colony is vulnerable to storms and to have gone undetected, it is unlikely that human disturbance at these sites. water-level changes associated with the province supports many more than British Columbia has many lakes, but downstream flood control. 200 nesting pairs. only a few meet the Western Grebe’s Threats on the wintering grounds In fall and winter, the provincial nesting requirements. These include: may include death or injury from oil population is swelled by migrants from warm water temperatures and a long spills, gill nets and pesticides, and breeding colonies as far east as Manito- ice-free period to allow the growth of decrease in prey availability due to over- ba, and possibly from the northern appropriate aquatic vegetation for nest- fishing by humans and degradation United States. Christmas counts on B.C.’s building; the presence of significant of estuaries. coastal waters have averaged about 20 000 populations of small, schooling fish; sta- in recent years. ble water levels; protection from wind What is their status? Because of its low breeding num- and waves; and deep water near the ased on Christmas bird counts along bers in British Columbia and the threats nesting area for feeding. The scarcity of the Pacific coast, biologists estimate to its nesting colonies, the Western suitable breeding habitat in B.C. is com- that the total population of the West- Grebe has been assigned to the provin- pounded by the fact that nesting is easi- B ern Grebe is over 100 000. They cial Red List of species being consid- ly disrupted by humans. The floating have been unable to determine whether ered for legal designation as Endan- nests are located in shallows along the the population is increasing, decreasing gered or Threatened. The Western edges of lakes and are easily tipped or or remaining stable. Nesting habitat Grebe is protected from killing or col- flooded by the wakes of passing has been lost in lecting by the British Columbia Wildlife boats. Excessive noise, human Although some areas, while Act and by the federal Migratory Bird activity and shoreline development alterations to the Convention Act. can also cause the grebes to aban- British landscape, such as don their nests. The best nesting Columbia reservoir construc- What do they look like? sites are medium to large lakes tion, have provid- rebes are highly specialized for swim- in the warm Southern Interior – has many ed new habitat ming and diving. They are seldom exactly the kinds of places favoured lakes, only in others. seen out of the water except when on by people for summer recreation. The number of G their nests. Their legs and feet are well Although nesting has been a few meet Western Grebes designed for providing strong propulsion recorded at about 14 locations in the Western that nest in British underwater – the legs are set far back on the province, some were not suit- Columbia is small. the body and the feet are lobed rather than able for maintaining colonies. Grebe’s nesting Our colonies have fully webbed like a duck’s. Colonies of five or more pairs are requirements. not been surveyed Six species of grebes are found in known to have existed at only five regularly, so we do British Columbia. The Western Grebe locations in B.C. and are now found not have accurate (Aechmophorus occidentalis) is our larg- at only three of those. The loss of former information about the trend in provincial est species, measuring about 64 centime- colonies at Swan Lake near Vernon and at abundance. We know that two former tres in length and weighing up to 1.8 Williams Lake is mainly attributed to the nesting colonies have been abandoned. kilograms. The Western Grebe is best dis- effects of human disturbance. At Williams Lake, where a colony of 5 to tinguished by its long, curved neck. It Two of the surviving nesting colonies 35 pairs was present in the 1930s and is the only one of our grebes that sports strongly contrasting black and white grebes. It is found in large groups at begins soon after the grebes reach their plumage year-round. Both sexes have the breeding colonies, on lakes during migra- nesting colonies in late April or early May. same colouring, but males are slightly tion and on the ocean in winter. They are readily observed at accessible larger than females. Clark’s Grebe, a closely related colonies like the one at Salmon Arm. The top of the head, It is species that was formerly thought The two main rituals are the “rush- the back of the neck to be a colour phase of the Western ing ceremony” and the “weed ceremo- and the upper parts unlikely Grebe, is an occasional visitor to ny.” During the rushing ceremony, two of the body are that the southern B.C.; nesting is extremely grebes engage in advertising calls and black to slatey-grey rare. The most obvious difference various head movements, then lunge in colour, while the province between these two similar species forward and run rapidly across the throat, the front and supports is that the dark head feathers of the surface of the water, side-by-side, for sides of the neck, and Western Grebe extend down below up to 20 metres. They do not call dur- the belly are white. many more its eyes, whereas the eyes of Clark’s ing the rush, but the pattering of their During the breed- than Grebe are surrounded by white feet on the water can be heard for some ing season, the black feathers. Their bills are also differ- distance. At the end of the rush they feathers on top of the nesting ent colours: Clark’s is orange-yel- dive. The rushing ceremony is believed head form a slight pairs. low, while the Western Grebe’s is to be important for attracting mates. crest. At close range, yellowish-green. The weed ceremony, which occurs this graceful grebe’s bright red eyes are later in pair formation, starts with vari- also discernible. What makes them unique? ous postures such as “neck-stretching” Even when not visible, the presence of he Western Grebe’s unique courtship and “bob-shaking,” after which both the Western Grebe is often revealed by its ceremonies have been studied exten- members of the pair dive and bring far-carrying call, a plaintive, high-pitched sively and are among the most complex up weeds in their bills. They then face “creek-creek” that is easily recognizable. T known among birds. The elaborate one another, feet churning to hold This grebe is more gregarious than other and energetic series of ritualized displays their bodies vertical, and move slowly forward or spiral with their weed-laden chicks riding on their parents’ backs. Present range of the bills held close together. This “weed They may travel several kilometres to Western Grebe dance” ends when one bird drops its where food is most available. Some- in Canada and the United States weeds, but the ceremony continues times the last egg is left behind. with further posturing. Newly hatched young spend only brief periods off their parents’ backs. How do they reproduce? Back-brooding lasts two to four weeks, ollowing several days of courtship, although the young still ride occasional- both members of the pair set to work ly until they are almost fully grown. building their nest. In B.C. this usual- Usually, one parent carries the brood F ly happens in May. The floating nests while the other dives for their food. At measure about 50 cm across and have a the end of a session of brooding, the soggy depression in the middle which carrying adult rises up in the water, holds the eggs. These small rafts flaps its wings and are made of aquatic vegetation The Western dumps the chicks in and anchored to plants like rushes the water. They then or pondweed. It takes about three Grebe’s climb onto the other days to build a nest big enough to unique parent’s back. The support a grebe, but the pair con- adults provide a tinues to add nest material during courtship foothold for the the laying and incubation period. ceremonies young by holding The eggs are laid one day one foot stiffly out apart. Pale blue when first pro- are among on the water surface been recorded in B.C. from April 29 duced, they become nest-stained the most to provide support. to August 31. Western Grebes usually over time. Clutches of one to As the chicks grow re-nest if the first nest is destroyed. seven eggs have been found in complex and the parents’ back Normally, new nests are constructed B.C., with three or four being known space gets too small each year, but late-nesting pairs may more usual. During the egg lay- to hold them all, the use a nest that has been vacated by a ing period, the male attends and among birds. dominant chicks get successful early-nesting pair. guards his mate, and both adults first access. vigorously defend the nest against The young birds are fed by their What do they eat? intruders. The eggs are incubated alter- parents until they are about eight mall fish make up 80 to 100 percent nately by both parents for about 24 weeks old, but may begin some diving of the Western Grebe’s diet, with days and are rarely left untended. Incu- before that. At about 10 weeks, their aquatic insects, crustaceans and bation bouts last several to many hours. flight feathers are fully grown and S worms comprising the remainder. One or two days before hatching, the they can fly short distances. The grebe thrusts its head forward like a young peep loudly from inside their Western Grebes have a fairly lengthy spear, impaling fish with its sharp bill. It eggs. Then they begin pipping (breaking nesting season. Incubating adults have also catches fish by using its bill like for- the shell). The precocial (well devel- ceps. A superb diver, the Western Grebe oped) chicks hatch at about one-day Present range of the Western Grebe in propels itself underwater with synchro- British Columbia intervals. As each one hatches, the par- nous thrusts of its hind feet, and can stay ents meticulously dispose of the submerged for a minute or longer. Small eggshells over the side of the nest. With- prey are usually swallowed underwater; in minutes of hatching, the downy but larger ones are brought to the surface still-wet chick emerges from under the and then consumed. rear of the incubating adult and climbs Freshwater feeding in British onto its back. The soggy nest cavity is Columbia has been studied only at not a suitable place for brooding, so CVWMA. Of the 10 kinds of fish that when all the young have hatched, the Former colonies occur there, only 2 were eaten: Yellow family leaves the nest for good with the Present colonies Perch and Pumpkinseed. These were probably selected because they are Many lakes in the southern half of year in response to changes in water level abundant and small enough for the the province are used during the east- and the distribution of emergent plants. grebes to swallow. These introduced fish ward spring migration to breeding sites, From about October to April Western are not widely distributed in B.C., and and the westward return to salt water Grebes are found along the Pacific coast different species are most likely eaten at in autumn. Lakes such as Okanagan, from southeast Alaska to Baja California. other nesting colonies. In British Columbia at this time of In their saltwater wintering year, they are most abundant in shel- sites, Western Grebes have been tered waters like Georgia Strait and reported to prey on a variety of Puget Sound, usually within two or small fish. Recent research near three kilometres of shore. Christmas Victoria suggests that some West- counts in some areas of coastal B.C. ern Grebes hunt at night because have averaged 500 to 5000 birds per the fish they feed on follow the ver- count. In the Southern Interior, tical migrations of plankton – by flocks of up to 100 grebes sometimes day, the plankton and the fish that winter on large, ice-free lakes. prey on them are at considerable depths, beyond the diving range of R. Wayne Campbell photo What can we do? the grebes, but at night they gather ince suitable nesting sites are so near the surface. Bioluminescent plank- Shuswap, Kootenay and Windermere are limited, conservation efforts ton organisms called dinoflagellates important stepping stones for tens of must focus on habitat protection swarm in these waters and emit light thousands of grebes heading for and S both for the grebes and for their when disturbed. Biologists believe that as returning from the prairie provinces, prey. These efforts should include: fish swim through these swarms, they and possibly the northern states. Flights obtaining protected status for the lakes leave a trail of light and unwittingly between lakes are always made at night. or parts of lakes where Western Grebes reveal themselves to the hungry grebes. Lakes used as stop-overs during nest; ensuring that the land surrounding Further research is needed to confirm migration are not necessarily suitable for the colonies is not subject to harmful this fascinating theory. breeding. Good nesting habitat must alterations; ensuring healthy aquatic Grebes are remarkable for the num- have emergent vegetation – plants ecosystems that ber of feathers they eat. The feathers like bulrushes, cattails or reed When all provide food for have no food value, but form a ball in canarygrass that grow in shallow the colonies; and the gut that is thought to keep fish water and extend above the water the young protecting nesting bones from injuring the lining of the surface. These are used to anchor have hatched, colonies from cur- stomach. They also help clean out indi- the nests, and provide some pro- rent and anticipat- gestible materials and may prevent the tection against wind and waves. the family ed human distur- build-up of gastro-intestinal parasites. Sometimes submergent plants leaves the bance. Minimizing may be used in the absence of threats on the win- Where do they live? emergents. Western Grebes also nest for good tering grounds is he aptly named Western Grebe require deeper water that sup- with the also important. lives only in western North America. ports large numbers of small fish British Colum- Its breeding range extends from near the nesting area. chicks riding bia’s three main T southern British Columbia east- Relatively stable water levels existing colonies – on their ward across the prairie provinces into are also very important. When at Shuswap and Manitoba, and south through the levels are unusually high, emer- parents’ backs. Okanagan lakes western states to northern Mexico. In gent plants may not extend high and at CVWMA – B.C., nesting has been recorded as far enough above the water to be useful for vary in their protection needs. The north as Williams Lake, but is mostly nesting. Levels that are lower than nor- Shuswap colony, directly in front of the restricted to low-elevation lakes in the mal may result in plant growth that is town of Salmon Arm, has received a lot dry Southern Interior, east to Creston. too dense for nesting or may strand the of conservation attention, including There are a few rare records of nesting nests on dry ground. Colony sites in marshland acquisition, control of shore- in coastal areas. any lake often shift slightly from year to line development and implementation “ .” . . Creston Valley Wildlife Management Area photo R. Wayne Campbell photo R. Wayne Campbell photo of boating restrictions at and near the suitable emergent vegetation and fish Protection of grebes from threats on nesting sites. This program, spearheaded populations. Being inside a conservation their ocean wintering grounds is complex. by the Salmon Arm Bay Nature Enhance- area where power boats are banned, this Since we do not know exactly where ment Society, benefits grebes and many colony is less threatened by disturbance members of our nesting colonies winter, it other species. This colony has been main- than the others. However, water levels are is difficult to determine effects of mortal- taining its numbers despite its close prox- controlled to prevent downstream flood- ity there on size of nesting colonies. How- imity to much human activity, a tribute to ing and may be unfavourable for nesting ever, protection of the nesting habitat of the efforts of local conservationists. In grebes. In addition, increasingly dense the Western Grebe in British Columbia, 1997, the public and business community cattail stands around the lake edge may including the ecosystems that support in Salmon Arm sponsored their first be forcing the grebes to nest in more their food supply, is a feasible objective annual Grebe Festival. Held in May, when exposed areas. Investigation of these and one worthy of public support. Their these easily observed birds are actively concerns is a high priority. continued presence as a breeding species courting along the Salmon Arm water- Studies need to be done at lakes where will contribute to this province’s rich front, the festival heightens awareness Western Grebes formerly nested to deter- biodiversity. We will also be rewarded about Western Grebes and raises funds mine why they have been abandoned. with the continuing opportunity to view for habitat protection and enhancement. Restoration of suitable habitat conditions the free show these uninhibited birds put At Salmon Arm, Ring-billed Gulls (a might induce the grebes to recolonize on each spring – an opportunity that Blue-listed species) have established a these sites. shouldn’t be missed. colony on an artificial island. Careful study is required to determine if the gulls , : may pose a threat to grebe eggs or chicks. Wildlife Branch The little-studied colony in the north Ministry of Environment, Lands and Parks arm of Okanagan Lake is potentially PO Box 9374, Stn. Prov. Govt Victoria, British Columbia V8W 9M4 threatened by disturbance from power www.elp.gov.bc.ca/wld boats and jet skis, and by lakeshore devel- opment. There are already campsites, trailer parks, summer cottages and boat ramps near the nesting areas. The nesting grebes here are probably affected by human activities, and further prolifera- tion of recreational activities could cause them to abandon the site. An action plan to preserve habitat and control distur- --- . bance is badly needed in this area. . , Western Grebes began nesting at Duck Lake in the 1960s when diking and water- level control in the CVWMA stopped excessive spring flooding and resulted in Printed in British Columbia on recycled paper with vegetable inks Q.P.4500015472