Two weeks ago I posted about the Ask the Experts live online chat that the Wisconsin DNR held on Oct. 31st about whooping cranes; the post covered all the chatter – questions and comments – about various aspects of the ultralight migration, and I wrote there that I would post again soon about all the other topics that came up in the one-hour Ask the Experts chat.
There was a lot, really. I won’t try to cover everything that was brought up, but there is a much to say about four particular topics. I’ll cover two of them in this post: first, black flies and the nesting season of the whoopers in Wisconsin, and second, the efforts by the Whooping Crane Eastern Partnership to establish a new flock of wild whooping cranes in Louisiana. In a final “Ask the Experts” post, I’ll cover two more: tracking cranes with backpack transmitters, and the issue of genetic bottlenecks. You can find links to the other “Ask the Experts” posts at the end of this one
The complete transcript of Ask the Experts is online, thanks to the DNR. The experts hosting the chat were Davin Lopez, whooping crane coordinator for the DNR, Heather Ray, associate director of development for Operation Migration, and the International Crane Foundation’s Eva Szyszkoski (field tracking manager) and Sara Gavney Moore (communications specialist).
Black Flies, Bti Treatments, and Nesting Season
Last year’s Ask the Experts whooping crane chat was distinguished by (as i recall it) many detailed, probing questions asking ‘when’ and ‘if’ and ‘why’ or ‘why not’ would Bacillus thuringiensis israelensis, or Bti, (a naturally occurring soil bacterium insecticide) be used to treat the anticipated outbreak of black flies during the cranes’ next nesting season. I was impressed by the level of knowledge, about both the issue and the proposed treatment, that the participants brought to the chat. And I was also impressed with the determination of the experts to essentially “leave no stone unturned” in their studying the issue before making a firm decision about this.
So what happened next? I’ll offer here a short summary of a very complicated issue and the series of events that made up the 2014 whooping crane nesting season. This is something that certainly requires a post of its own before 2015’s nesting season. For now, though, here’s a short version:
A decision was made not to use the Bti (which had been used experimentally in the 2011 nesting season with some apparent success), leaving a group of dissatisfied people who closely follow the progress of the whooping cranes. The experts that make up the Whooping Crane Eastern Partnership had decided on an alternative to using an insecticide – which would, they contended, alter the ecology of the habitats for all the wildlife at Necedah National Wildlife Refuge, for the benefit of just one species.
Their plan, instead was to attempt to manipulate the cranes nesting behavior by removing the eggs from one half of the cranes first nests. These cranes would likely build new nests and lay more eggs. By the time of the second nests, the annual “black fly bloom” would be over, and the pesky insects would not be present to torment the cranes sitting on nests.
Frankly, that seemed like a creative potential solution to me, but in spring 2014 Mother Nature was creative too, essentially muting the experiment. The cold spring meant that the black fly bloom didn’t occur at all during the first nesting season (13 chicks were hatched, one survives the dangers in the wild that befell the other 12). There wasn’t much of a second nesting season and by then, I believe, the black flies were indeed a-blooming.
So. Back to this year’s chat: there a few questions about using Bti, (but nothing like the many asked a year ago) the first being, really, why not just use it “on the dreaded black flies?” Davin Lopez, the Wisconsin DNR’s whooping crane coordinator agreed that it was a possibility, “if we can get the permits, but we are currently exploring changing nest phenology as a way to get around the black fly issue.”
“What is changing nest phenology?” he was asked, and explained that it meant removing eggs from the nest (and raising in captivity any chicks that result) to force renesting.
Two more questions concerned the renesting. Not all the pairs that have had their eggs removed will do that, Davin affirmed, and Heather Ray of Operation Migration fielded a similar question: ” . . .will the birds renest that same season after the flies are gone?”
“Occasionally, yes,” said Heather. “It really depends on how far along in the gestational process the original eggs were.”
Let’s move on now to –
The Whooping Cranes in Louisiana
If last year’s whooping crane chat was dominated by questions about Bti treatments, the one two years ago (the first one I ever participated in) seemed to be all about the efforts to establish a new flock of wild whooping cranes in Louisiana. There were a lot of questions about it; and some concerns that it might be taking chicks away from our Wisconsin-based Eastern Migratory Population (EMP)?
The Louisiana efforts began in 2011, with two different cohorts of birds sent from the captive populations of whooping cranes to the White Lake Wetlands Conservation Area. Unlike the EMP, the Louisiana flock will be non-migratory. But what it does share with the EMP is that they are both managed by the Whooping Crane Eastern Partnership and both seek to advance the same over-arching goal – to establish a new self-sustaining flocks of wild whooping cranes.
This year’s participants wanted to know how many birds are in the Louisiana flock right now (27 individual birds) and when will the next cohort be transferred from the captive population at Patuxent Wildlife Research Center and how many individual birds will be in it? (13 or 14 new chicks are due to be transferred into the Louisiana flock in early December).
There was a question about where would these 13 or 14 chicks come from and “why such a large number compared to the other programs?” Heather Ray explained that each reintroduction flock (the EMP and the one in Louisiana) gets an equal number of birds, but the chicks allocated to the EMP get split up for three different release methods: the ultralight-led class, the direct autumn release method, and, for the second year in a row now, a release of 4 chicks that have been parent-reared at Patuxent.
Why have a non-migrating flock? Historically there was a non-migratory flock in Louisiana, Davin Lopez answered. “The cranes do not need to migrate, “due to the ecology of the area . . . We are trying to reintroduce the same type of population.”
More from “Ask the Experts:”