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.

Share

Counting Whooping Cranes

Wondering what is involved with counting whooping cranes?

Each fall, the natural wild flock of whooping cranes migrates the 2,500 miles from their nesting grounds at Wood Buffalo National Park in Alberta, Canada to Aransas National Wildlife Refuge for the winter. They live on the Texas coast a few months of the year and they spend that time feeding in the remote wetlands of the refuge and surrounding area. So how do U.S. Fish and Wildlife Service biologists estimate the number of whooping cranes in existence today? The answer: long hours in a small plane flying a grid and looking very, very closely at what is happening on the ground.

While the whooping cranes are in Texas, researchers conduct surveys by plane to gauge the status of the population. They fly several flights and while flying a grid pattern over the refuge, they have to be able to discern which birds are whooping cranes. Can you find the whooping cranes in the photo below?

Counting Whooping Cranes
Birds on the ground, viewed from the survey plane (original photo: Tom Stehn)

 

The data collected from the flights is used to calculate an estimate of the wild whooping crane population. If you would like to see more photos and read more details about how USFWS conducts their aerial surveys on the Aransas NWR, click here.

Counting whooping cranes is not an easy task and FOTWW thanks the USFWS for taking the time and going into detail on how the surveys are conducted.

***** 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.

wind farm
friendsofthewildwhoopers.org
Share

Public Encouraged to Report Sightings of Whooping Cranes

Wildlife agencies asking for help

The entire population of whooping cranes in the Central Flyway is expected to migrate through Nebraska and North Dakota over the next several weeks. The Nebraska Game and Parks Commission and the North Dakota Game and Fish Department encourages the public to report whooping crane sightings. Information on crane sightings is used to positively affect whooping crane conservation and recovery efforts.Wildlife agencies in Nebraska and North Dakota are seeking the public’s help in reporting whooping crane sightings as they make their spring migration through the two states.

Nebraska reports

If you see a whooping crane in Nebraska, please report your whooping crane sighting to Nebraska Game and Parks (402-471-0641), U.S. Fish and Wildlife Service (308-379-5562), or The Crane Trust’s Whooper Watch hotline (888-399-2824). Emails may be submitted to joel.jorgensen@nebraska.gov.

North Dakota reports

If you see a whooping crane in North Dakota, please report your whooping crane sighting to, U.S. Fish and Wildlife Service offices at Lostwood, (701) 848-2466, or Long Lake, (701) 387-4397, national wildlife refuges; the state Game and Fish Department in Bismarck, (701) 328-6300;; or to local game wardens across the state.

Should you see a whooping crane, please do not get close or disturb it. Keep your distance and make a note of date, time, location, and what the whooping crane is doing.

Reason for reporting

You may wonder why the wild life agencies are asking for these sightings to be reported. The reports are very helpful in gathering data and information on when and where the whooping cranes stopover, what type of habitat they are choosing, and how many there are.

With just over 300 wild whooping cranes migrating along the Central Flyway, odds are low of seeing a wild whooping crane. However, FOTWW hopes that someone reading this article will be one of the lucky few and if you are, please report your sighting so that these agencies and other conservation groups, including FOTWW can continue helping these magnificent cranes.

 

Wildlife agencies seeking help with whooping crane sightings.
Whooping Cranes in Flight. Photo by Charles Hardin.

 

***** 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.

wind farm
friendsofthewildwhoopers.org
Share

Debate about counting Whooping Cranes continues

by Friends of the Wild Whoopers

Not all Whooping Cranes counted

Whooping Cranes
Whooping Cranes over Aransas NWR.  Photo by Kevin Sims ©2105

 

Aransas Wildlife Refuge biologist Tom Stehn conducted Whooping Crane census flights for 29 years at Aransas during which he tried to find every crane.  When Tom Stehn retired from U.S. Fish and Wildlife Service (USFWS) in 2011, the agency changed from doing a weekly Whooping Crane census to conducting a survey that takes place for roughly one week every December.  The change to a survey incorporated a technique called distance sampling where not every crane is counted but estimates of the cranes not seen are based on how far observed cranes were from the aircraft when sighted.  This statistically-derived method provides 95% confidence limits for an estimated Whooping Crane population.  Unfortunately, those confidence limits are quite large, equaling plus or minus 39 cranes out of an estimated flock of 338 during the winter of 2016.

Monitoring Whooping Cranes, Comparison article published

Dr. Bruce Pugesek and Tom Stehn, in January, 2017 published an article in the Proceedings of the 13th North American Crane Workshop entitled “THE UTILITY OF CENSUS OR SURVEY FOR MONITORING WHOOPING CRANES IN WINTER”.  The article compares the survey and census methods of counting Whooping Cranes.  An abstract for this paper is provided below, along with a link to download the entire 10-page article.

Tom Stehn commented to Friends of the Wild Whoopers about the article as follows:

“The article is not an easy read, but that’s the way science sometimes works.  It is a rebuttal of some of the things that USFWS wrote regarding their crane survey method.  In the article, Dr. Pugesek and I point out problems with the survey, including statistics, as well as what we consider as some of the “falsehoods” contained in what was written trying to justify the survey instituted after I retired.  I feel the USFWS was overly critical with unfair and overstated criticism of the census method that USFWS had done for 60 years.  And I firmly believe that with very thorough coverage of the crane area combined with the knowledge I had of individual cranes and their territories accumulated over 29 years of work and over 400 census flights, I could estimate the size of the whooping crane population in a manner much more accurately, and with a justifiable estimate of winter mortality, than what is being done on the current survey method.  The bottom line is that a census is usually stronger scientifically than a survey if the species’ biological parameters allow a census to be conducted.”

Tom continues: “If current USFWS policy requires that a survey with confidence limits be continued, I recommend that after the annual survey is completed, that additional funds be spent doing a census in a manner similar to what I used to do.  Doing some additional flying will allow comparison of the former census method with the current survey results which will provide more information about the crane population as well as better assess the survey methodology currently being employed.  A census would involve thorough coverage of the crane range with transects no more than 500 meters apart.  If there are now more cranes and a bigger area to cover, do the census over 1.5 days if need be.  Also, territories of all family groups should be determined, with a follow-up flight or two in early March to show which juveniles have died during the winter.  This estimate of annual winter mortality is very important, given what is known about drought and reduced inflows related to increased whooper mortality.”

ABSTRACT:

THE UTILITY OF CENSUS OR SURVEY FOR MONITORING WHOOPING CRANES IN WINTER
BRUCE H. PUGESEK,
1 Department of Ecology, Montana State University, Bozeman, MT 59717, USA
THOMAS V. STEHN, 1613 South Saunders Street, Aransas Pass, TX 78336, USA

Abstract: We discuss recent changes in the monitoring program for endangered whooping cranes (Grus americana) on their winter habitat in Texas. A 61-year annual census was replaced in the winter of 2011-2012 with a distance sampling procedure. Justification for the change was, in part, based on criticism of the previous methods of counting cranes and the assessment of crane mortality on the wintering grounds. We argue here that the arguments, methods, and analyses employed to discount the census procedure and mortality estimates were applied incorrectly or with flawed logic and assertions. We provide analysis and logical arguments to show that the census and mortality counts were scientifically valid estimates. The distance sampling protocol currently employed does not provide the accuracy needed to show small annual changes in population size, nor does it provide any estimate of winter mortality. Implications of the relative merit of census and mortality counts versus distance sampling surveys are discussed in the context of management of the whooping crane.

Link to article

***** 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.

wind farm
friendsofthewildwhoopers.org
Share