Sandhill Cranes

FUN AND INTERESTING TRIVIA ABOUT CRANES:

 

1) There are two subspecies of Sandhill Cranes in California- the Lesser Sandhill Crane and the Greater Sandhill Crane.  Pixley NWR has the Lesser Sandhill Cranes.

2) Lesser Sandhill Cranes stand about 3 ½-feet tall, with a 6-foot wing span, and weigh about 7 lbs.; the males are larger than the females, and the juveniles, called colts, are even smaller. The pair mate for life, and the family group stays together throughout migration and on their wintering grounds; the young cranes will stay with their parents for over 9-months; look for these family groups.

3) The prominent red forehead patch is not made up of feathers, but is actually a bald area free of feathers, exposing its red-colored skin. Sandhill Cranes can actually pump more blood to this area, like blushing, to make their forehead even redder. These cranes use this red forehead patch for territorial disputes to show aggressive behavior during nest building. Just like some humans, some cranes are very bald, and therefore show the entire top of their head as red. Colts have feathers on their foreheads, so they don’t show a red forehead patch until they lose their forehead feathers later in the winter.

4) Our Lesser Sandhill Cranes breed during the summer in the far north, primarily in Alaska, and then migrate 2,500 miles south, arriving back at the Pixley NWR in late-September, where they will stay and feed until they migrate back north to breed in March. Sandhill Cranes show a high fidelity to both their nesting and wintering locations, returning annually to the exact same sites; this makes them very vulnerable to rapid population declines due to changes in their habitat (and in other States-hunting).

5) Sandhill Cranes are mainly herbivorous, feeding primarily on newly planted and harvested grains, and will dig into the ground with their bill for roots and tubers; however, they are also somewhat omnivorous, and will also eat mice, small birds, lizards, frogs, and insects. One serious problem is that more and more grain fields are now being converted to vineyards that provide no feeding opportunities for the cranes. During the day, the cranes feed in the grain fields; in the evening they all fly into the freshwater wetlands at Pixley NWR to rest, wading in the marsh throughout the night, where they are safe from predators like coyotes and foxes. (A coyote splashing through the water would certainly alert the cranes to danger). These cranes prefer marshlands with water levels about 6” deep; during the fall and winter, the water levels are maintained at the Pixley NWR at a depth between 5” and 10” deep, which is also an optimum feeding depth for many species of ducks.

6) Coyotes, wolves, bobcats, foxes, raccoons, alligators, eagles, and Peregrine Falcons are the main predators of Sandhill Cranes. Ravens will eat their eggs. Sandhill Cranes often vigorously defend themselves from predators, especially when defending offspring. When attacking potential avian predators they fly up at the predator and kick with their feet. When facing mammalian predators, they move toward the predator with their wings open, and hiss with their bill pointed towards it. If the predator persists, the crane will attack, stabbing with their bill, (which is powerful enough to pierce the skull of a small carnivore), and kicking with their feet.

7) A 10 million-year-old Miocene crane fossil found in Nebraska is structurally identical to the modern Sandhill Crane, making Sandhills Cranes the oldest known surviving bird species, This fossil was found with ancient forms of a barrel-bodied rhinoceros, saber-toothed deer, five species of ancient horse and three species of ancient camels; these species are now all gone, yet Sandhill Cranes still walk this earth today; these birds are essentially living fossils!

8) Herons and egrets are often mistakenly identified as cranes since they all have very long legs that dangle far beyond their tail when they fly. However, unlike herons and egrets, cranes always fly with their necks outstretched, not pulled back. Also, cranes cannot perch in trees, while herons and egrets perch and actually nest in trees; a crane has a very reduced back toe, so it won't get tangled in wetland vegetation, but this also means it can't perch in trees.

9) Sandhill Cranes are very long-lived, with birds surviving over 20-years in the wild, and over 40-years in captivity; one crane even lived 80 years in captivity! Not surprisingly, a Sandhill Crane will usually not pair-up and nest until it is at least three years old, and often not until it is seven or eight years old! Unless a mate dies, Sandhill Cranes form lifelong pair bonds.

10) Sandhill Crane nests are typically constructed of vegetation in shallow water (usually less than 12 inches deep). Vegetation is plucked and stacked to form a mound. These are often very large, two to three feet high and up to six feet in diameter. The birds will often remove every bit of vegetation for many feet around the nest, forming circular areas known as "pluck zones." Two eggs are usually laid.  Both parents share equal duties in building the nest, incubation, and feeding and caring for their young (colts).  A colt’s diet initially consists of high protein invertebrates such as aquatic and terrestrial insects.

11) Many Sandhill Cranes have rusty-brown stains on their feathers due to smearing mud rich in iron oxide (rust) onto their feathers with their bills; this may help them be more cryptic.  The Sandhill Crane is one of only two crane species to stain its feathers- the other being the European Crane. The Lesser Sandhill Crane is also called the “Little Brown Crane” due to this feather staining. At least one individual at the Pixley NWR is virtually entirely rusty-brown; it really stands out from the others due to extensive feather staining.

12) Sandhill Cranes can fly at speeds ranging from 12 to 50 miles an hour! The Lesser Sandhill Cranes wintering at the Pixley NWR will migrate over 2,500 miles to northern Alaska in March to breed. With their 6-ft wingspan and excellent ability to use thermals, Sandhill Cranes can travel long distances without much flapping, thus expending very little energy. Sandhill Cranes must run on the ground in order to take flight.

13) “Sandhill” Cranes are named after the “sandhills” in Nebraska. The Sandhills is a region of mixed-grass prairie on grass-stabilized sand dunes in north-central Nebraska, covering just over one quarter of the state.

14) The typical rattling "kar-r-r-r- o-o-o" sound from a male crane are lower pitched than the female’s calls; these bugling calls can travel a very long distance, and can even be heard from over a mile away! Juvenile cranes (colts) make a very different call, a very high-pitched squeaky-sounding “tweer.” During mating, pairs vocalize in a behavior known as "unison calling," to reaffirm their life-long pair bond.  They throw their heads back and unleash a passionate rapid synchronized duet, with the female making two notes for every single note by the male. While performing these trumpet-like staccato “unison calls,” the male will point his beak vertical in the air, while the female will call with her beak at an angle to the male’s beak.

Like nearly all birds, Sandhill Cranes have lightweight hollow bones that also contain part of their respiratory system to allow for more efficient breathing. The windpipe (trachea) of these cranes is actually wrapped INSIDE its keeled breastbone (sternum), which helps to produce their strange rattle-like calls.

15) There are fifteen living species of cranes and an additional 36 extinct species. North America has only two species of cranes—Whooping Cranes and Sandhill Cranes.  Of the 15 living species, the Sandhill Cranes are the most numerous with 600,000 now staging along the Platte River in Nebraska each March and April, while another 250,000 visit California. On the other hand, several other crane species rank among the world’s most threatened birds. The Whooping Crane is one of the rarest birds in North America; conservation measures brought it back from only 15 birds in the 1940’s to 437 birds now living in the wild (with 264 wintering in the Aransas NWR in Texas), and an additional 165 in captivity today.

The Greater Sandhill Crane subspecies, which breeds in Northern California and winters in the Central Valley, is a California-listed threatened species; in California, the breeding population was reduced to fewer than five pairs by 1944, but restoration efforts since then have raise the Greater Sandhill Cranes population in California to an estimated 8,500 individuals.

16) The greatest threat to Sandhill Cranes (as well as all crane species) is habitat loss and degradation. The Pixley NWR was once the shoreline of the historic 800,000-acre Tulare Lake, which, at the time, was the largest freshwater wetland in California. This lake has since disappeared because of the building of dams on the rivers and the diversions of water to agriculture and development. In its heyday, Tulare Lake undoubtedly supported millions of wintering ducks, geese, and swans, thousands of White Pelicans, and hundreds of thousands of Sandhill Cranes.

17) Market hunting of Sandhill Cranes in California between 1850 and 1915 also had a severe impact on crane populations. Even as early as the mid-1850’s, cranes reportedly were always available in San Francisco markets to replace the Christmas turkey, frequently selling for $18 to $20 apiece.

 

The following sentence from Forsberg’s “On Ancient Wings” regarding Sandhill Cranes seems to also apply to the Pixley NWR: “One thing is for sure. If this place one day has no cranes, it will have lost its spirit, and the soul of this remnant landscape will wither.”

 

For more information about upcoming programs, events, and field trips, please visit the Tulare County Audubon Society website:http://tularecountyaudubon.wix.com/tularecountyaudubon

 

 

 

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