Flor­ida Sand­hill Crane

Pro­tected as a threat­ened species by the Flor­ida FWC

Times of the Islands - - Departments - Wil­liam R. Cox has been a pro­fes­sional na­ture pho­tog­ra­pher and ecol­o­gist for more than 35 years. Visit him on­line at williamr­cox­pho­tog­ra­phy.com.

The sand­hill crane has been split into six sub­species, in­clud­ing two in Flor­ida: the res­i­dent Flor­ida sand­hill crane (Grus canaden­sis praten­sis) and the mi­gra­tory greater sand­hill crane (G. c. tabida). The for­mer sub­species nests in Flor­ida, while the lat­ter nests in the Great Lakes re­gion. The Flor­ida sand­hill crane ranges from the Oke­feno­kee Swamp in Geor­gia south through most of the Flor­ida penin­sula. Its pop­u­la­tion in early 2000 was es­ti­mated to be 4,000 birds. The greater sand­hill cranes win­ter in Flor­ida from Oc­to­ber through March. These two sub­species can be dis­tin­guished only by be­hav­ioral dif­fer­ences. The greater sand­hill crane is more eas­ily dis­turbed by hu­man en­croach­ment, and its roost­ing and feed­ing flocks are larger than the Flor­ida sand­hill crane.

Dur­ing mi­gra­tion the greater sand­hill crane flies in a tight V- or U-shaped flock. The Flor­ida sand­hill crane flies in a loose lin­ear flock. Both types of sand­hill cranes fly with their legs and neck ex­tended; their wing up­stroke is snappy, while the down­stroke is slow. In com­par­i­son, herons such as the great blue heron have evenly paced down­strokes and up­strokes, and the neck is curled back in flight.

The adult Flor­ida sand­hill crane stands 4 feet tall with a 6-foot wingspan. Fe­males and males weigh about 9 and 10.4 pounds, re­spec­tively. Both sexes have gray plumage that some­times is stained a red­dish brown. The sand­hill crane’s head ex­hibits white cheeks and a red crown. Ju­ve­nile birds have brown necks and heads and achieve adult-like ap­pear­ances at 10 to 14 months of age.

The best way to de­ter­mine sex is by lis­ten­ing to the male and fe­male “uni­son calls.” The male’s voice is lower pitched than the fe­male’s. The fe­male’s call is two to three times shorter in du­ra­tion than the male’s. A mated pair of­ten duets at dusk and again at dawn from their nest. Sand­hill crane calls can be heard two to three miles away.

Adults reach sex­ual ma­tu­rity at two to three years but are more likely to have a suc­cess­ful clutch at five years. The nest­ing sea­son in Flor­ida is from Jan­uary through June. Nests are 3 feet in di­am­e­ter and are built 6 to 7 inches above stand­ing wa­ter. The eggs are olive brown. Clutch size is nor­mally two eggs, which are in­cu­bated by both sexes for 29-32 days. The young hatch a day apart. The hatch­lings are pre­co­cial (born in an ad­vanced stage of de­vel­op­ment) and usu­ally leave the nest within 24 hours. Ac­ces­sory nests are built within 150 feet of the pri­mary nest as day­time rest sites for the young and for brook­ing hatch­lings at night.

The young are ca­pa­ble of flight within 2-2.5 months, and they leave the fam­ily unit in 10 months. Home range of an in­di­vid­ual sand­hill pair av­er­ages 1,100 acres. The de­fended nest­ing

Sand­hill cranes fly with their legs and neck ex­tended; their wing up­stroke is snappy, while the down­stroke is slow.

ter­ri­tory ranges from 300 acres to 625 acres. Mat­ing pro­duc­tiv­ity is high­est dur­ing win­ters with more rain­fall, which pro­duces more suit­able nest­ing sites. Pro­duc­tiv­ity is lower in years with high spring rain­fall be­cause of nest flood­ing or be­cause wet­lands be­come un­suit­able for nest­ing.

Shal­low wet­lands that are 10 to 14 inches deep and dom­i­nated by maiden cane and pick­erel­weed are pre­ferred by the Flor­ida sand­hill crane for nest­ing. It for­ages in ad­ja­cent and es­sen­tial open up­lands and dry prairies, with veg­e­ta­tion mostly 18-20 inches tall. It is also ob­served in wet prairies, open wood­lands, im­proved pas­tures, ranch­lands, sod farms, sub­ur­ban sub­di­vi­sions, air­ports and golf cour­ses. It feeds on a va­ri­ety of an­i­mals and plants, in­clud­ing seeds, acorns, tu­bers, roots, corn, peanuts, dew­ber­ries, blue­ber­ries, mice, rats, small birds, frogs, snakes, drag­on­flies, cray­fish and grasshop­pers.

The Flor­ida sand­hill crane is listed as a state-threat­ened species by the Flor­ida Fish and Wildlife Con­ser­va­tion Com­mis­sion (FWC) be­cause of its low re­pro­duc­tive po­ten­tial, vul­ner­a­bil­ity to pre­da­tion, non­nat­u­ral mor­tal­ity and loss of habi­tat. Egg preda­tors in­clude fish crows and rac­coons. The young and some adults are preyed upon by bob­cats, coy­otes and many other preda­tors. The young are also preyed upon by free-roam­ing cats and dogs. Adult non-nat­u­ral mor­tal­ity in­cludes dis­eases, col­li­sions with util­ity lines, road kills and get­ting en­tan­gled in fences.

Nest­ing sand­hill cranes are sen­si­tive to hu­man en­croach­ment ac­tiv­i­ties, and thus a 400-foot buf­fer has been rec­om­mended by sci­en­tists to pre­vent nest aban­don­ment caused by hu­man dis­tur­bance. Every­one should be aware that sand­hill cranes are wild an­i­mals and can be dan­ger­ous dur­ing the nest­ing sea­son.

The Flor­ida sand­hill crane prefers to nest in shal­low wet­lands. This one was pho­tographed at Harns Marsh in eastern Lee County.

Flor­ida sand­hill cranes with their young, which are born in an ad­vanced stage of de­vel­op­ment and usu­ally leave the nest within 24 hours

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