457 Whooping Crane Eggs Taken from Canada’s Nesting Grounds

The Unison Call, – Newsletter of the North American Crane Working Group –
Vol. 27 No. 2, The Fall/Winter 2016-1

457 Whooping Crane Eggs Taken from Canada’s Nesting Grounds – Enough is Enough!
By Chester McConnell, Friends of the Wild Whoopers

Whooping Crane Eggs

Top: Two whooping crane eggs in a nest in Wood Buffalo NP (photo: Libby Gunn). Bottom: Whooping crane adult at its nest site in Wood Buffalo NP (photo: John McKinnon).

An astonishing 457 whooping crane eggs were removed from nesting grounds in Canada’s Wood Buffalo National Park (WBNP) from 1964 to 1998 to be used in several experimental population projects and to establish (or augment) captive breeding programs. The eggs were taken from the only self-sustaining wild population of whooping cranes in the world, which is known as the Aransas-Wood Buffalo population (AWBP). The significance of such management decisions cannot be overemphasized. As of 2016, the AWBP numbers an estimated 329 birds. We can only imagine how much larger the AWBP would be today if the 457 eggs had not been removed. Certainly, not all of the eggs would have produced birds that would have survived and added to the population, but some would have.

Importantly, we need to recall why the eggs were removed. There was concern during the 1940s (and subsequently) that the AWBP could become extinct. Only 18 whooping cranes remained in that population in 1944-45. By 1967 there were just 9 nesting pairs. The U.S. Fish and Service (USFWS) and Canadian Wildlife Service (CWS) decided to make an attempt to help the species.

The two agencies made well-intentioned efforts, based on information at the time, to safeguard the AWBP, by establishing and then increasing the numbers and genetic diversity in the captive flocks used to produce eggs and, starting in 1975, by trying to establish new wild populations in new locations. Some of the repopulation attempts were failures, while others are still ongoing (with outcomes still unknown). Even so, there have been, and continues to be, serious differences of opinions about the various efforts and especially those involving taking whooping crane eggs from nests in WBNP.

Removal plans for whooping crane eggs

The egg removal plan involved taking one egg from nests with two eggs. (Technical information in this article is summarized from the International Recovery Plan for the whooping crane 2007, Appendix C, Egg Collection, pages C1 through C5.) The decision to collect one of two eggs from wild nests was made in 1965. Research personnel had learned that, although whooping cranes normally lay two eggs, only about 15% of families arriving on the Aransas National Wildlife Refuge (ANWR) wintering area have two chicks. Therefore, about 85% of nests usually contain one egg that is unlikely to result in a fledged chick. However, the second egg plays an unknown role in providing insurance that at least one chick survives. Habitat conditions, including water levels, food availability and predator abundance, affect survival. In years with suitable habitat conditions, crane pairs may raise two young. For example, during the 1958-59 winter, 8 of the 9 young that arrived at Aransas were from twin pairs. In 1997 and 1998, at least 9% of second-hatched whooping crane young survived to fledging age.

During the 61-year period from 1938 to 1998, there were 34 years in which no egg collection occurred at WBNP (mostly pre-1967). In those 34 years, 16 pairs of ‘twin’ juveniles arrived at ANWR in the fall. During the 27 years of egg collection at the nesting grounds, no pairs of twin juveniles arrived at ANWR in the fall (Cannon et al., 2001).

Brief history of whooping crane eggs taken

Eggs were first taken from 1967 to 1971 and in 1974 to further augment the Patuxent Wildlife Research Center (PWRC) captive population. More eggs were taken from 1975 through 1988 to provide 215 eggs for the Grays Lake cross-fostering experiment. Egg transfers to PWRC were resumed in 1982-1989 and 1991-1996, with 178 eggs being transferred. Fifty-eight eggs were transferred to the International Crane Foundation (ICF) beginning in 1990 and resumed in 1992-1996. Six eggs were shipped to the Calgary Zoo in 1994 and 1998, and a chick was transferred there from WBNP in 1999. Two eggs from an abandoned nest were picked up opportunistically in May 1998 and transferred to Calgary Zoo. Between 1967 and 1998, 244 eggs were taken from WBNP to the captive sites.

Effects on population growth rate

The effects of egg collection on the growth rate and overall fitness of the wild AWBP are unknown. There was, and remains, much disagreement among whooping crane professionals. Some contend that egg removals have not adversely affected the productivity of the wild population (e.g. Ellis and Gee, 2001). They point out that between 1967 and 1996, the era of egg pickups, the AWBP increased from 48 to 160, and the number of nesting pairs increased from 5 to 45. After reviewing and critiquing the several research findings, James Lewis, USFWS (retired biologist), in 2001, concluded that the data as presented did not support the views of Cannon et al. (2001) and determined that a re-analysis of the existing egg collection data was warranted (Lewis, 2001).

CWS biologist Brian Johns (retired) reviewed the data pair by pair and extracted as much information as possible from original reports and solicited the expertise of Dr. Mark Boyce, University of Alberta, for the analysis (Boyce et al., 2005). However, it’s been suggested that the data set used has biases, including: non-random nest selection; lack of a control group; not testing eggs for viability in the early years of collection; limited samples in certain years; and potential inaccuracies in chick surveys. Because of these issues, it is not possible to say what impact egg pickup has had on the size of the AWBP.

Some reintroduction programs benefited

The Whooping Crane International Recovery Team (IRT) recognizes that collection of eggs has benefited the whooping crane recovery program by providing stock to establish the captive flocks and providing offspring for release, thus increasing the total number of whooping cranes (cranes artificially reared and released into the wild) and helping to preserve the genetics of the species. The IRT in 2007 believed that data analyses to date did not indicate that egg collection would increase recruitment in the AWBP over the long term, but could increase recruitment in selected years.

In 2016, the IRT initiated a process to update the International Recovery Plan for the Whooping Crane, 2007 (IRP-2007). The goal is to incorporate new information and techniques, with the overall goal of down-listing and eventually fully recovering the species. A whooping crane population viability analysis (PVA) process is being used to produce information to be included in an upcoming version of the IRP.

The PVA would include whooping crane egg harvest on WBNP as one of several management scenarios that would be considered. According to Wade Harrell (USFWS) (personal communication), “That does not necessarily mean that we will harvest eggs from nests, only that we are considering it as we model a number of different management scenarios. If the PVA models indicate that it would provide significant benefit to the population, we would consider it further as we look at political, logistical and cost constraints of various management scenarios. So, to be clear, no decisions have been made.”

FOTWW’s beliefs

Friends of the Wild Whoopers (FOTWW) is opposed to any additional collection of wild whooping crane eggs from WBNP. Based on several unpublished communications, we believe that poor parenting skills of captive-reared whooping cranes and/or habitat quality is the reason for the serious problems in the Eastern Migratory Population. According to the genetic master plan, the genetic diversity of the AWBP is well represented in the three captive flocks, hence there would be little to be gained genetically in the captive flocks by removing additional eggs from WBNP at this time. Genetic experts have recommended that, as a minimum before any additional eggs are picked up from the wild, a large-scale genetic study is needed in WBNP, since information on the composition of nesting pairs has been lost with the cessation of color-banding in 1988 (IRP 2007). Frozen semen banks should be maintained to prevent loss of founder lines. A national serum bank should be set up to serve as a repository of genetic material for the species.

FOTWW is not critical of experimental projects preformed in the past including the Gray’s Lake cross-fostering experiment and the augmentation of the PWRC whooping cranes. Such early projects were learning experiences and measures to help save the species. Yet it is inexcusable to waste more eggs taken from nest of the only remaining population of self-sustaining whooping cranes to repeat past failures.

FOTWW believes all eggs should remain in the nest on WBNP because there is no convincing need to take more.

References

Boyce, MS, SR Lele, BW Johns (2005) Whooping crane recruitment enhanced by egg removal. Biological Conservation 126:395-401.

Canadian Wildlife Service and U.S. Fish and Wildlife Service. 2007. International recovery plan for the whooping crane. Ottawa: Recovery of Nationally Endangered Wildlife (RENEW), and U.S. Fish and Wildlife Service, Albuquerque, New Mexico. 162 pp. (pages 51-52)

Cannon, JR, BW Johns, TV Stehn (2001) Egg collection and recruitment of young of the year in the Aransas/Wood Buffalo population of whooping cranes. Proceedings North American Crane Workshop 8:11-16.

Ellis, DH, GF Gee (2001) Whooping crane egg management: options and consequences. Proceedings North American Crane Workshop 8:17-23.

Lewis, JC (2001) Increased egg conservation: is it essential for recovery of whooping cranes in the Aransas/Wood Buffalo population? Proceedings North American Crane Workshop 8:1-5

Chester McConnell, President of FOTWW wrote the above article. He has worked for whooping cranes for 20 years in several capacities. Most recently as FOTWW’s President he has visited military bases and Indian Reservations throughout the whooping crane migration corridor in 7 states. He advises the military and Reservation personnel about how to develop and manage “stopover habitat” for the cranes. He also writes detailed management plans for all sites he visits. He is now being recruited to provide the same services for other areas along the migration corridor. McConnell and Pam Bates are the co-founders of Friends of the Wild Whoopers. McConnell also served with Whooping Crane Conservation Association for 12 years. He served as WCCA’s President, Board member, webpage manager and editor of their news letter.  McConnell also served as a wildlife biologist with Tennessee Wildlife Agency and as Wildlife Management Institute Representative for 31 years where he was involved with a variety of wildlife species and their habitats. He has a Masters of Science in Wildlife Biology.

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Cows helping Whooping Cranes

by Chester McConnell, FOTWW

Friends of the Wild Whoopers is continuing its project to encourage development and management of stopover habitats for migrating Whooping Cranes. We have visited military bases, Indian Reservations and some private lands within the six state migration corridor (TX, OK, KS, NE, SD and ND). Our mission is to provide advice to land managers about how to develop and/or manage existing ponds/wetlands to be useful as roosting/feeding sites for migrating Whooping Cranes. The cranes must stopover approximately 15 to 20 times during their 2,500 mile migration between Canada’s Wood Buffalo nesting area and their wintering area at Aransas Refuge on the Texas coast.

Some management relationships discovered

During our field trips to the various sites we have learned about some management relationships that we had not been aware of. We learned that livestock, including cattle and bison can make some ponds/wetlands more suitable as stopover areas. Livestock normally walk around ponds until they reach a shallow area where they can safely enter the ponds and drink. As they are moving around they are also grazing and trampling vegetation on pond shores. Whooping Cranes use these same shallow areas with sparse vegetation to enter the ponds to roost. We observed this relationship on numerous ponds/wetlands especially in North and South Dakota.

Whooping Cranes avoid certain sites

Whooping Cranes do not use ponds/wetlands as stopover sites where tall, dense vegetation closely surrounds the pond shore. They avoid sites anywhere they would have to move through dense vegetation where predators may be lurking such as shown in Figure 1.

Whooping Cranes

Figure 1. This pond’s shore area is covered with a dense growth of cattail vegetation. Whooping Cranes will not attempt to use ponds with these conditions. When selecting a pond where they can roost for the night, the cranes glide in (Fig. 2) and land on the shore. Then they walk into a shallow area of the pond and roost where they are safer from predators. Predators such as coyotes and bobcats can hide in dense vegetation and jump on Whoopers and kill them.

Whooping Cranes

Figure 2. Whooping cranes gliding onto shore of nearby pond. They will observe their surroundings to look for danger. Then they will walk into a shallow area of the pond to roost for the night. Because of their long legs and 5 foot height, they can defend themselves against predators while roosting in water. Whoopers landng by Diane Nunley

Fortunately, around some ponds, livestock have grazed and trampled the vegetation while getting a drink and grazing the more succulent vegetation (Figure 3).This results in more unobstructed shore areas that allow Whooping Cranes to use ponds as stopover sites.

Some concern has been expressed that livestock cause shoreline erosion and contamination of the stock dams/ponds that results in some murky, dirty water. While this may have some merit, FOTWW did not detect any serious problems. We carefully observed the water in the ponds visited and could clearly see the pond bottom in shallow areas. We also firmly believe that the advantages of the stock dams/ponds far outweigh any disadvantages. Use of the ponds/wetland water resources by numerous species and many thousands of individual wild animals has caused the military and Indian Reservation’s habitats to be much more productive.

Some ponds in excellent condition

Some of the stock dams/ponds on the areas visited are currently in excellent condition to serve as secure Whooping Crane stopover habitats. And some other ponds/wetlands could easily and inexpensively be developed into good habitats. However others are not useful for Whooping Cranes because cattails, bushes and trees are thick along the shore areas. On these latter ponds FOTWW recommends that they be managed for other wildlife species that prefer dense vegetative cover.

Importantly, FOTWW contends that it is not necessary or desirable to modify or manage all ponds for Whooping Cranes but rather focus on a subset with the best ponds and surrounding landscape characteristics. Open landscapes including pasture and crop land allows Whooping Cranes to easily locate the ponds and provides ready observation of any predator threats.

Whooping Cranes

Figure 3. Pond with cattle grazing on Cheyenne River Indian Reservation, South Dakota. Note that vegetation around portions of the shore is short (A) while cattail (sp.) invasion has been restricted (B) due to livestock grazing. The shallow area (C) within the pond would provide roosting sites for Whooping Cranes.

***** FOTWW’s mission is to help preserve and protect the Aransas/Wood Buffalo
population of wild whooping cranes and their habitat. *****

Friends of the Wild Whoopers is a nonprofit 501(c)3 organization.

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friendsofthewildwhoopers.org

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