Spring and Whooping Cranes arrive at Wood Buffalo NP

by Pam Bates

Spring is here and a few Whooping Cranes from the wild flock have arrived on the nesting grounds at Wood Buffalo National Park, (WBNP).

Whooping Cranes arrive at Wood Buffalo
Photo by Klaus Nigge. Click to view at full size.

According to Rhona Kindopp, Manager of Resource Conservation, Parks Canada. “they have been hearing and observing a number of spring arrivals in the last week or two and one of their staff members reported seeing (and hearing) 4 whoopers flying as she walked home from the office!”

Kindopp states that they are getting signals from 12 cranes marked with transmitters, and those as of Tuesday morning were coming from North and South Dakota, Kansas and Texas, and central Saskatchewan. So the flock is still spread out along the Central Flyway and heading to WBNP.

Nesting Ground conditions.

Numbers regarding whether precipitation was significantly lower than usual this year aren’t available at this time but Kindopp says that the “snow disappeared very quickly this spring. March is usually our heaviest snow month, but the snow was quickly disappearing by mid-March this year.”

Friends of the Wild Whoopers will publish updates of the nesting ground conditions and any ongoing Whooping Crane chick reproduction and related activities when it is available.

Whooping Cranes nesting information

Whooping cranes usually arrive at WBNP during late April and May after migrating 2,500 miles from Aransas Refuge on the Texas coast. Each nesting pair locates their nesting site which is normally in the same general area as past years. Park records show that several pairs have nested in the same areas for 22 consecutive years. Soon after their arrival on their nesting grounds, they build their nest. Nesting territories of breeding pairs vary in size but average about 1,500 acres. Whooping Cranes guard their territories and nesting neighbors normally locate their nest at least one-half mile away. Vegetation from the local area is normally used for nest construction and they construct their nests in shallow water.

Eggs are usually laid in late April to mid-May. Normally two eggs are laid but occasionally only one and rarely three have been observed in nests. Incubation begins when the first egg is laid. Incubation occurs for about 30 days. Because incubation starts when the first egg is laid, the first chick hatched is a day or two older than the second hatched. This difference in age is substantial and creates problem for the younger chick. It is weaker than the older chick and has difficulty keeping up as the adults move around searching for food. The younger chick often dies due to its weakness. Records indicate that only about 10% to 15% of the second chicks hatched survive.

Importantly, the second egg plays an important role in providing insurance that at least one chick survives. From the time Whoopers begin egg laying until their chicks are a few months old, the family groups remain in their breeding territory. They feed there and don’t move long distances until after their chicks fledge.

Report any sightings

With a few cranes already on the nesting grounds, the majority of the flock is still migrating north. Parks Canada is requesting if you see any whooping cranes, they would love to hear from you! Contact the Park Office at 867-872-7960.

***** 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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Wood Buffalo’s Whooping Crane Aerial Survey

by Sharon Irwin, Resource Management Officer, Wood Buffalo National Park, Canada

Since the discovery of nesting Whooping Cranes in Wood Buffalo National Park (WBNP), the Canadian Wildlife Service (CWS) and WBNP have conducted aerial surveys to monitor the population. Aerial survey techniques involves flying a combination of circular flights and transects over known nesting territories and similar looking marshes likely to contain breeding Whooping Cranes. These aerial surveys account for nearly 100% of the breeding Whooping Cranes each year.

In August 2014 CWS staff were unavailable to lead the fledgling survey so I became the Survey Lead and Navigator. The pilot, Mark Rayner, WBNP staff Queenie Gray, Jane Peterson, Amy Lusk and I spent 4 days flying over the Wood Buffalo nesting area in an attempt to locate the whoopers and their chicks.

Eurocopter EC120 Colibri used during Wood Buffalo Whooping Crane arial survey. L-R: Queenie Gray, Amy Lusk, Sharon Irwin and pilot Mark Rayner.
Eurocopter EC120 Colibri used during Wood Buffalo Whooping Crane survey. L-R: Queenie Gray, Amy Lusk, Sharon Irwin and pilot Mark Rayner.

Breeding pair surveys are done in mid to late May over 4-5 days with a crew of 2-3 made up of Parks Canada staff and Canadian Wildlife Service biologists.  Breeding pairs normally use the same territory each year to build their nest and raise their chicks. Knowing where the cranes nest helps make locating the adults and juveniles a bit more successful.

whooping crane aerial survey
GPS connected to a laptop computer with a mapping program called ArcPad.

A Eurocopter EC120 Colibri has been the preferred aircraft for the last couple of years.  It has an enclosed tail rotor which makes it quieter than other helicopters of its size. The helicopter flies at an altitude of about 1,000 to 1,200 feet above ground level (AGL).  The person in the front seat next to the pilot is the navigator.  They use a GPS connected to a laptop computer with a mapping program called ArcPad.

The program allows us to have multiple layers showing at any time our map. We usually have the rivers and ponds showing as well as last year’s nesting locations.  The map has an icon to show where we are flying and draws a trail showing where we have been.  Blocks are flown with transects that are one kilometer apart in the areas where Whooping crane nests have been found in the past.  If the team thinks that a pair of Whooping Cranes may have been missed, we go to the location of the nest from previous years and fly a spiral working out from the nest. The other personnel on the helicopter are observers and collect data as a backup on a GPS, another laptop and in a notebook.

whooping crane aerial survey
Queenie takes GPS points and notes in the backseat of the helicopter.

Each evening after the survey the staff spends a few hours sorting out the data and trying to figure out which pairs of Whooping Cranes have and have not been found for an area.  Frequently a return flight is required to go back to an area to find a missing pair. It really depends on the light conditions, on how easy it is to spot a Whooping Crane.  Sometimes we can see them from a couple of kilometers away and other times we just can’t find them.

The fledgling survey is done in between the end of July and mid-August.  Fledglings are birds that have reached an age where they can fly. The technique for this survey is very similar to the breeding pair survey.  The nest locations are known so we can fly right to the nest.  It may be more efficient in areas where the cranes are more spread out to use the spiraling technique to locate the family group.  In areas where the nests are close together, it seems easier to use the transect method.  In some cases we end up using both techniques.  If the Whooping Cranes have not been successful in raising a chick they may still be in their territory or they could be kilometers away.  Unless they are banded birds, it is almost impossible to figure out which nest a pair used.  If a pair does have a chick, they are generally found fairly close to their nest.

Both the Nest Survey and the Fledgling Survey are part of the world-class restoration plan that has made the Whooping Crane an international success story and symbol of species recovery and conservation. By counting the number of fledgling chicks, Parks Canada, Canadian Wildlife Service, US Fish and Wildlife Service, and others gain important insights into the health of the world’s last remaining natural nesting flock that contribute greatly to our ongoing stewardship of these magnificent birds.

A record number of 164 Whooping Cranes were counted incubating their eggs in 82 nests during the annual survey in June 2014.  This number surpasses a previous record of 76 nests in spring 2011.  These endangered birds all nest in and around WBNP, Canada. The mission of the survey was to determine how many chicks had hatched and survived to become fledglings since the nest counts were made in June.

WBNP officials reported that a total of 202 whoopers were counted, including the fledgling and nesting pairs.  The 32 fledglings were found in 30 family groups: 28 families with one chick and two families with two chicks. In addition to the family groups, the surveyors observed 6 groups of three whooping cranes, 43 groups of two, and 6 individual cranes.

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

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Wood Buffalo Whooping Crane Chick Survival Rate

The only surviving self-sustaining migratory population of wild whooping cranes nests in Wood Buffalo National Park (WBNP) in Northern Alberta. Their breeding grounds are an area of boreal spruce forest growing on narrow ridges. (Figure 1.) The adult whooper pairs that nest there protect their hatchling chicks in accordance with some natural traits that man does not fully understand. The adults, and especially the young, face many difficulties.

Figure 1.   Whooping crane nesting habitat on Wood Buffalo.                   Photo by Klaus Nigge
Figure 1. Whooping crane nesting habitat on Wood Buffalo. Note whooping crane on nest left-center of photo. Photo by Klaus Nigge

Every year WBNP’s staff and the Canadian Wildlife Service join together to do two aerial surveys on the whoopers nesting grounds. In June the first survey is made to count the number of whooping crane nest. The second survey is made in August to determine the number of chicks that fledged (capable of flying).

WBNP officials reported that during 2014 that the survey team counted a record of 82 nest in June and 32 fledgling whooping cranes during August. In 2013, the survey team spotted 74 nests in the spring and 28 fledglings later in the summer. “That gives a success rate of about 40% when compared to how many fledglings we have when compared with the number of nests they started out with in the spring”, according to Stuart McMillan, Manager, Resource Conservation, WBNP. The success rate is based on an assumption of the survival of one chick per nest (more on this later).  The surveyors observed 28 pairs with one fledgling chick, and two families with two fledgling chicks during 2014. Friends of the Wild Whoopers regards the 32 fledglings as a very good survival level.

So, what happened to the nest or chicks that may have hatched between the June and August surveys? Sixty percent of the nest did not produce chicks or, if they did, those chicks did not survive until the August survey.

The Aransas/Wood Buffalo population of whooping cranes needs many things in order to survive and reproduce. They need suitable breeding grounds, a reliable food source, an unpolluted habitat, a safe migration path and a healthy wintering area. Based on biological evaluations, WBNP does provide suitable, unpolluted breeding grounds with a reliable food source. So what are the limiting factors that caused either a 60 % nest failure or chick deaths between the June and August surveys?

Eggs are normally laid in late April to mid-May, and hatching occurs about one month later. The incubation period is from 29 to 31 days.  Around 90% of the clutches contain two eggs.  Whooping cranes may re-nest if their first clutch is destroyed or lost before mid-incubation.  Egg predation is believed to be uncommon at Wood Buffalo NP, and re-nesting has only been documented a few times.

Figure 2.  Raven taking egg from whooping crane nest on Wood Buffalo.  Photo by Klaus Nigge
Figure 2. Raven taking egg from whooping crane nest on Wood Buffalo.    Photo by Klaus Nigge

There are several animals that prey on the eggs and young of whooping cranes.  Some examples are the American black bear, wolverine, red fox, gray wolf, lynx, bald eagle, golden eagle and raven. Adult whooping cranes have very few predators because of their large size.While the listed critters are potential nest predators, they are rarely a threat to adult whoopers.

Figure 3. Raven flying away holding leg of whooping in egg. Photo by Klaus Nigge
Figure 3. Raven flying away holding leg of whooping crane chick while chick is still in egg.    Photo by Klaus Nigge

The cranes build their nests in shallow waters as one means of protection.  While in water it is more difficult for predators to catch adult whoopers unaware. Yet, while on land, it is easier for stealthy predators to creep up on them. Overall impact of predation on recruitment remains uncertain.

Chicks are particularly vulnerable until they are about 3 months old when they fledge (begin to fly). They are even more vulnerable in dry summers when water levels are low and nesting areas are more accessible to predators.

Whooping crane parents remain alert for evidence of predators and alarm calls may be given at sight of large predators.  And, the parents may approach and threaten or attack small predators such as red fox. They may also give a distraction display toward a large predator such as a bear or wolf. Yet, the best efforts of the adults are not always successful in saving their chicks from predators.

Figure 4. Red  foxes on Wood Buffalo may raid nest or catch chicks.  Photo by Ronnie Schaefer
Figure 4. Red foxes on Wood Buffalo may raid nest or catch chicks. Photo by Ronnie Schaefer

From the time whooping crane chicks are hatched to the time they are adults, chicks and juveniles face many hazards. They may face death from predators, injuries, inadequate food and sickness. Scientists working with the cranes have estimated that approximately one-third, or less, of wild whooping crane chicks survive from hatching to breeding age.

So, again, what has happened to the nest or chicks that may have hatched between the June and August surveys? The answer is that we do not know precisely. But a research study performed from 1997 to 1999 provides some of the best information available to help us understand. That part of WBNP where the whooping cranes nest and rear their young is a huge wetland area. It is difficult to move around in the wetlands and to cover sufficient territory to perform detailed biological studies to learn about whooping crane problems. So, what we do know at this time is based on a few, but very informative biological studies and general observations on a sample of the whooping crane population.

A study of the survival and death rates of whooping crane colts (chicks) in WBNP was accomplished by personnel of Parks Canada and Canadian Wildlife Service from 1997 to 1999. The purpose of the study was to provide baseline information on causes of chick mortality and to gain information on why few whooping crane twins survive. Researchers used intensive aerial monitoring, ground observations and radio-telemetry to monitor twenty-two whooping crane pairs that had twin chicks in WBNP.

Transmitters were attached to 18 chicks hatched by the 22 adult pairs.  Five (28%) of the chicks fledged (capable of flying); five (28%) succumbed to cumulative effects (head trauma, stress, exposure and infection); four (22%) were lost to unknown causes (three of these went missing after they had lost their transmitters).

Research personnel believed two chicks (11%) had been taken by a fox (Vulpes vulpes), one (5.5%) was lost to raven (Corvus corax) predation, and one (5.5%) died of pneumonia. Out of the 22 sets of twins monitored, one set of twins survived the summer. On another occasion the older sibling was taken by a fox and the younger chick survived. This resulted in 9% of the smaller sibling chicks surviving. Chicks being monitored that went missing did so between 7 and 22 days following hatching.

Interestingly, the researchers observed that most often it is the younger (smaller) sibling chicks that go missing for several reasons.  The first chick to hatch (from the 2 eggs in a nest) is at least 2 days older and is heavier. The older chick displays severe aggression by repeatedly pecking the younger one, sometimes causing injury (head trauma, stress and infection). Then, the family groups depart the nest pond soon after the 2nd egg hatches and is on the move for the first week following hatching. All of these factors work together in wearing down most of the smaller sibling chicks and within 2 weeks the younger chick has perished or is unable to keep up with the family group and gets abandoned. Such natural conduct  is distressing  for humans to comprehend.

Based on their study the researchers determined several factors work against twins whooping crane chicks surviving. These include direct causes like predation from foxes and ravens, and indirect causes such as trauma (which the researchers believe to be primarily the result of sibling aggression), exposure and infection.

The research team wrote: “We believe the following scenario may be common in WBNP. Once the second eggs hatches, the older sibling displays aggression towards the younger colt, this aggression can be severe at the nest site as the colts are confined to a small area. The adults depart the nest pond when the younger colt is approximately two days old and the physical demands involved in keeping pace with the family wears down the younger colt. Over time the younger colt becomes weaker, lags behind and becomes vulnerable to predators or eventually is abandoned. While this may be the case generally, we did have two occasions where the younger colt fledged. We believe that the second (younger) colt acts as insurance in case the older colt dies in the first critical weeks of life. We believe that every wild whooping crane recruited into the Aransas-WBNP wild population is critical to the survival of this population and the long-term viability of the species. We therefore recommend that it is necessary to leave nests in WBNP with two eggs and let natural selection work to increase the fitness of the only self-sustaining wild population of whooping cranes in the world.”

by Chester McConnell, Friends of the Wild Whoopers

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

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Whooping Crane Stopover Study To Aid Species Recovery

In March, Friends of the Wild Whoopers reported on the need to learn more about resting/feeding sites along the whooping crane migratory route. (See Whooping Crane Tracking Study) In order to learn more about the Aransas-Wood Buffalo whooping crane population needs during migration, the Whooping Crane Tracking Partnership began banding and tracking them in 2009. Banding of the whooping cranes has been completed and preliminary findings are currently being compiled. Many key areas have already been identified where the whooping cranes stop over during their 2,500 mile migration. Other useful insights “into this here-to-fore little-know world of whooping crane stopover habitat” are being studied.”

In their latest Newsletter, the Crane Trust offers us some more insight and details about the Whooping Crane Tracking Partnership’s study.

 

Article from Crane Trust Spring 2014 Newsletter

Whooping cranes require suitable stopover sites to complete their spring/fall migration. Without them, the 5,000-mile journey would not be possible. Photo by John Conklin, Canadian Wildlife Service.

Suitable habitat for whooping cranes to stop, rest and feed during their spring/fall migration is critical for the Aransas-Wood Buffalo population to complete its 2,500-mile journey each way. These stopover sites are the focus of a comprehensive ground-based study to improve our understanding of the specific habitats and locations selected by whooping cranes during their migration—and are vital for the species recovery. Above Photo: Whooping cranes require suitable stopover sites to complete their spring/fall migration. Without them, the 5,000-mile journey would not be possible. Photo by John Conklin, Canadian Wildlife Service. 

Measuring

Initiated in 2012 by the Platte River Recovery Implementation Program and researchers from the Crane Trust and the US Geological Survey, the ground-based study was in full swing for the 2014 spring migration. To date, more than 250 stopover sites have been visited and characterized by researchers between northern Texas and North Dakota. The result to date is the most exhaustive aggregation of data ever collected on whooping crane stopover sites and their utilization by migrating cranes.  Above Photo: Maximum depth was one of over a dozen water-related measurements taken at sites where water was present. Distance to water, bank slope, land cover of nearest shoreline, and wetland classification were among the others.

Mapping

Individual stopover sites were located using GPS tracking data from the Whooping Crane Tracking Partnership’s telemetry study and were visited by one of three regional research teams. Each team spent roughly one day in the field for every two days in the office contacting landowners and collecting/inputting time-sensitive measurements. Key measurements and their application included 360° on-location photography, GIS mapping of habitat types and land covers, food types and availability, land cover and management practices, endangering and visually obstructive features, water characteristics (if present), and other variables.  Above Photo: The Crane Trust’s Ryan Joe creates GIS map of stopover site using field data collected this spring. The finished product will depict key features and habitats, providing a valuable reference for visual analysis.

Panorama

The precise arrival and departure times of the whooping crane(s) and their movements within each stopover site area were also recorded. Sites were visited after whooping cranes had departed, so as to not disturb migrating birds and to record observations and measurements as close to the bird’s departure as possible.  Above Photo: Habitat variations and similarities were observed throughout the migration corridor. The above photo was indicative of a stopover site in the Nebraska-central region.  

While complete study results aren’t expected until 2015, preliminary findings are already providing useful insights into this here-to-fore little-known world of whooping crane stopover habitat. When complete, the Platte River Recovery Implementation Program, the Crane Trust and other conservation organizations/agencies will be able to use this comprehensive data to better inform (and improve) habitat management practices and conservation strategies to aid the species recovery.

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

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