Species Spotlight July 2022

Growing up Sandhill Crane

We are all waiting expectantly for the successful fledging of our second Sandhill Crane colt. We are also waiting eagerly to be able to walk our Kiwa Trail.  So, what is taking so long?  Well, it may not take a village to raise a Sandhill Crane colt, but it certainly takes a pair of adults a lot of time and attention.

How it starts:  Before a nest is even started, the adult pair takes two to four weeks to establish a suitable territory. Our pair were seen in March showing interest in the Kiwa Trail area again.  A nest territory usually has several potentially useful nest sites. Once selected one of the pair, usually the female, stands on a mount and arranges nest material provided by both.  The nest area may have several elevated platforms for brooding and feeding the young.  Generally, nest initiation starts from early April to late May: the farther north, the later the start. Based on the hatch date for our colt, we believe the egg laying this year was first week of April.  Throughout most of the

species’ range, the presence of standing water with emergent aquatic vegetation is an important characteristic of the nest site.  The Kiwa Trail area certainly fits the bill there. Sandhill Cranes generally construct nests in water where floating piles of aquatic vegetation, grass, mud, sticks, and moss separate vulnerable eggs and chicks from terrestrial predators. Think about our coyotes.  Both sexes participate in construction that may last 1 day to two weeks. The finished product can vary in size between 30 inches wide up to 50 inches in length. Throughout incubation, the sitting bird may add small amounts of material and continually rearrange the nest.

Sandhill Cranes will lay one to three eggs per clutch at two-day intervals, but the mean clutch size is less that 2 per pair.  The egg is pale brownish buff to light olive, irregularly marked with darker brown, reddish brown or pale gray and is about 3 ½ by 2 1/3 inches in size.  Both males and females develop brood patches, and both incubate the egg(s).  Average incubation length is 30 days. Nests are usually attended constantly, but the female predominantly sits the nest at night, giving her 70% of total incubation duties. Older, experienced birds are better at attending the eggs than younger birds according to some studies.  As eggs move through incubation their tolerance to temperature fluctuations improves.

Get me out of here:  When young start to vocalized in the egg about 72 hours before hatching, adults will give “purrs” in response.  This may help stimulate hatching.  The young bird will pip the egg or break the egg from inside. They have three calls during this stage:  a Contact Call, a Pipping Call, and a Stress Call. Within 20 hours of pipping, the chick begins rotating counter-clockwise and breaks the shell. That can take over 7 hours.   Hatchlings are nidifugous. That is, they leave the nest soon after hatching. Their down dries with 2 to 3 hours by which time their eyes are open. They can sit up and sometimes even stand feebly. And it doesn’t take long for them to stand well. For our colt, the hatch was the first week of May.

Feed Me:  The young, at about four ounces, leave the nest within twenty-four hours of hatching and begin feeding. During the first ten days or so after hatching chicks are mainly fed bill-to-bill by parents. Cranes are omnivores and pretty much eat anything. The chicks are fed emergent vegetation, invertebrates and small vertebrates.  The adults will tear apart the larger pieces for the young colts. Studies have shown the chicks growing to eleven ounces in the first twelve or so days and by thirty days of age, young acquire about half of their adult leg and wing length. By forty days after hatching, legs are almost full-grown and two months, bill and wings are nearly adult size.  However, they will not complete their growth until they are almost a year old.  The more northerly subspecies grow faster than the southerly nesting subspecies.  Young become more self-feeding after half grown. Still food items may be dropped at the feet of young by adults leading them to feeding opportunities.

In the first 2 to 3 weeks after hatch, the chicks may be brooded on the adults back or under their wing. The adults along with the young will stay close to the nesting area to begin with but increase their range daily until they have expanded to the whole nesting territory at fledging. Fledging, when the colt takes its first flight, can vary from 7 to 10 weeks after hatching depending on the subspecies.  For our local family of cranes, 70 days to fledging seems to be the target according to our biologist. With the first flight, the young are quick to become strong fliers. They can take care of themselves by that time but will stay in the family group until the next first spring migration.  The parents will continue to provide feeding opportunities and protection from predators until they move out on their own.
So, where is our current family now?  Not sure.  They need at least a hundred days from egg-laying to fledging.  Last year we were able to open the Kiwa Trail by July 31st.  Staff will need time for trail maintenance to fill in holes and take down that abundant vegetation, none of which they can do while the family is still in the area.  By end of July and with hopes for a successful fledgling flight?  That’s how you grow up Sandhill Crane.

-Susan Setterberg, Contact Station Volunteer
images by Anne Myers & USFWS