A word about cranes

The Sandhill Crane that nests in two or three locations around where I live is one of 15 species in the world. I've seen nine of them--so far.
Cranes in Traditional Thought
Throughout East Asia, cranes, which mate for life and live many years (~30 years in the wild; ~40 in captivity), are known to bring good luck, especially a long life of happiness and marital fidelity to couples. Their images, especially of the red-crowned crane (Grus japonica), are common motifs in Japanese, Chinese and Korean art and crafts. For the Katzie First Nation, Sandhill Cranes, syahaha’w (meaning “superior in everything”), are guardian spirits generally and impart particular skill to women in their work (Jennes 1955, cited by Leach, 1987). Cranes were created when two sisters, who were digging Indian potatoes (Sagittaria latifolia), mocked and laughed at Khaals, a supernatural being. Khaals then transformed them into cranes, “henceforth to roam the meadows and to laugh and dance after rooting up the ground food as the two sisters did” (Jennes 1955, cited by Leach, 1987).
A Katzie elder who was born about 1880 recalled to Jennes (1955, cited by Leach, 1987) his father, Old Pierre, saying that cranes used to arrive “in their thousands” in the marshes around Pitt Meadows. This and Lulu Island (Munro and McTaggart-Cowan, 1974) were the main lower Fraser Valley breeding areas.
Crane Migration along the West Coast of Canada
At least 3500 Sandhill Cranes (evidently a mixture of lesser Sandhill Cranes, Gus canadensis canadensis, and Greater Sandhill Cranes, G. c. tabida) commonly pass Cape Flattery, Washington, and enter British Columbia en route to breeding territories along the coast and islands of British Columbia and southeast Alaska (Mattocks 1985 cited in Campbell et al., 1990). Around 100 Sandhill Cranes gather a farm at Northey Lake north of Comox each fall during migration (Kathleen Fry, Reifel Island Migratory Bird Sanctuary, pers. comm. December 27, 2009). These are presumably G. c. tabida en route to breeding areas on the north coast of BC, on the Queen Charlotte Islands, or Alaska.
Between 22,000 and 25,000 large Sandhill Cranes, probably C. c. rowani , follow a separate route through interior grasslands, passing through Penticton, Williams Lake, and east of Smithers. A few Sandhill Cranes also migrate along the west side of the Cascade and Coast Ranges.
From the time that the first written records were kept until about 1918, Greater Sandhill Cranes bred in all the major bogs of the floodplain of the lower Fraser Valley and the Pitt River Valley (Leach, 1987). By 1983, hunting, disturbance, and habitat loss had reduced this population to three breeding pairs at Pitt Polder and a non-breeding summer flock at Burns Bog. A major source of habitat loss was evidently the diking and draining of the Fraser River floodplain, which prevented annual flooding from keeping the open “prairie” habitat free of shrubs and trees (North and Treversham 1976, cited by Leach, 1987).
Lower Mainland Populations
In 1979–1983, an attempt at recovery was made by hatching, tagging, and releasing 17 surviving young from 34 Greater Sandhill Crane eggs from Grays Lake, Idaho and one from the Pitt River Valley (Leach, 1987). This was apparently successful, banded birds having been seen for some years afterwards, but it could not overcome the continuing habitat loss and disturbance.
An estimated 50 cranes annually stage at Burns Bog prior to the fall migration; these probably comprise local birds mixed with migrants from more northerly nesting areas up the BC coast (Jeglum et al., 2007). Counts of fall migrating birds suggested a total Lower Fraser Valley population of about 24 birds (Gebauer, 1999). There are three breeding locations (Figure 4), raising the possibility that they may be a metapopulation with three subpopulations.
Lulu Island/Burns Bog Population
Brooks (1917, cited by Gebauer, 1999) mentioned that cranes nested in the large cranberry bogs in the vicinity of New Westminster, which may have been on Lulu Island or in Burns Bog. The highest reported number of breeding cranes for Burns Bog was in 1945, when a Mr. Luscher reported eight breeding pairs (Biggs, 1976). By 1947, Munro and Cowan (1974) considered the coastal population of cranes to be restricted to Lulu Island. In 1975, Biggs (1976) reported only one pair of breeding Sandhill Cranes that fledged one chick in Burns Bog. Either the earlier reports resulted from incomplete surveys or the population subsequently increased, because from 1994 to 1999 the number surveys at Burns Bog remained around 10–21 birds comprising 2–4 pairs plus non-breeding individuals (Gebauer, 1999).
Pitt Polder
Leach (1987) summarized the decline of the Pitt Polder breeding population in the 1970s and early 1980s based on notes and two typescript manuscripts of Wilma Robinson: five immature and nine adults that produced four fledglings in 1975, five nests with one juvenile in 1976 (when there was disturbance and habitat loss), two nests seen and a third presumed, and two young produced, in 1977, one or possibly two nests and no young in 1978, three pairs attempted to nest without success in 1979, 1980, and 1981, and three pairs nesting and one young produced in 1982. Leach (1987) reported one pair with one juvenile in 1983.
Reifel Island Population
During 1994–1997, I noticed that the tame, wing-clipped female that lived at the Reifel Island Migratory Bird Sanctuary for many years was occasionally accompanied by another crane in the spring and that both exhibited courtship behaviour (Harding, unpubl. observations). In about 1998, she mated with a wild male and produced a chick that did not survive (Kathleen Fry, Reifel Island Migratory Bird Sanctuary, pers. comm. December 27, 2009). The adult female subsequently died. The wild male, however, mated with another wild female and for the last 16 years or so the pair (presumably the same two individuals) has nested every year and produced a chick nearly every year. This pair may not be the same subspecies, as one is larger. The chick produced in 2009 did not survive, however. No more than one pair has ever nested at Reifel; however, another pair nests every year by No. 7 road in Richmond (not Burns Bog) and these two pairs sometimes associate. The flock (presumably the pair and its progeny) now numbers 12 adults and does not migrate. Each fall more birds appear—migrants from up the coast—and the flock numbered 14 all fall of 2009 and at one point reached 25. As many as 40 have staged there in past autumns prior to migration (Kathleen Fry, Reifel Island Migratory Bird Sanctuary, pers. comm. December 27, 2009).
THREATS
Habitat loss is obviously the greatest threat to the lower mainland population and also threatens other populations in the Interior. At Burns Bog, habitat is continually whittled away by berry farms and transportation eating into its edges. At Pitt Polder, blueberry farms every year take a bigger chunk.
A pair of captive Florida Sandhill Cranes (G. c. pratensis) hatched a chick in 2007 and another in 2008, one of which survived and remains in captivity at the Greaver Vancouver Zoo. In 2009 the pair nested again but the male died and the eggs failed (email from Jamie Dorgan, Chief Veterinarian, Greater Vancouver Zoo, June 7, 2009). The facility is fenced but not enclosed from above. This raises the possibility of genetic contamination of native birds, should these captive birds escape, or if a native bird were to mate with the captive female.
References
For brevity, references are not posted here but are available on request.