You know that old saying “Don’t count your chickens before they hatch”, well those of us in the whooping crane world don’t follow that rule very well. In fact each year we count our cranes before they hatch, we sometimes even count eggs before they’re determined to be fertile or even before they’re laid! Every spring the flock managers at the 5 captive breeding facilities “look into their crystal ball” and make a prediction about how many fertile eggs their flock will produce that year. The prediction is based on the history of the birds and years of records but ultimately it’s still somewhat of a guess because all kinds of unpredictable things can occur. Unfortunately this year turned out to be one of those years with more unpredictable events than normal. It was a warm, early spring and several facilities had birds lay eggs earlier than usual which meant they hadn’t been covered by artificial insemination and ended up being infertile. Some birds at Patuxent Wildlife Research Center (PWRC) laid single eggs instead of the normal two egg clutch and some birds started molting early, perhaps due to the warm weather. The International Crane Foundation (ICF) had a valuable and very productive female die and the Calgary Zoo discovered that a reliable pair of birds had started breaking their eggs rather than protecting them and incubating them. All of this resulted in a not so good year for whooping crane egg production.
Back in February the International Whooping Crane Recovery Team met in Texas to discuss all things whooping crane as well as decide the general allocation of chicks between the two current reintroduction projects – Louisiana (LA) and the Whooping Crane Eastern Partnership (WCEP) which is reintroducing a migratory population of whoopers in the eastern US. Their decision was essentially a 50:50 split between the two efforts. Within WCEP there are several different types of projects or release techniques so their 50% gets further divided between the ultralight-led technique (UL) and the direct autumn release (DAR) technique.
Eggs are easier to ship than chicks and since eggs are produced at several facilities other than those that end up raising the birds there are a number of egg shipments that occur throughout the spring. DAR chicks are hatched and raised at ICF while UL and LA chicks are both hatched and raised at PWRC. UL chicks are generally the earlier chicks and LA chicks tend to be the later ones. However, because we’re guessing how many more eggs might be laid and how many chicks will actually hatch as we go along sometimes LA chicks start out as an UL chick and even initially get trained with the ultralight aircraft. Our desire, of course, is for them to have as little of this training as possible but several of our chicks from the first 2 releases have had some UL training and it doesn’t seem to have impacted them so we allow some flexibility with chicks that will ultimately become LA birds.
As the spring went on and production continued to look poor 2 of the original UL chicks were pulled for LA and it looked like 2 more would likely be pulled later. Last week the final decision was made with the last egg shipments having occurred and nearly all the eggs hatched, so the final UL bird was pulled to join the LA cohort. Not all chicks survive so we’re getting ahead of ourselves again but the final allocation of birds looks to be: 6 UL chicks, 8 DAR chicks, and 13 LA chicks. While not as many as we had hoped to get this year and in fact smaller than our 2011 release cohort we’re still excited to get another group to release and we realize there are good years and bad years and unfortunately this year was just one of the bad ones.
Thanks to Jane Chandler for sending along these cute pictures of future LA chicks!
Update written by Sara Zimorski