NEST DESERTION IN A REINTRODUCED POPULATION OF MIGRATORY WHOOPING CRANES

Reintroduction of an eastern migratory population of whooping cranes (Grus americana) into eastern North America began in 2001. Reproduction first occurred in 2005. Through 2008, eggs were produced in 22 first nests and 2 renests. All first nests failed–50% confirmed due to desertion by the parents and the remaining nest failures also consistent with the pattern of parental desertion. Nest failures were not related to stage of incubation, and they were often synchronous. Temperatures in winter and early spring affected timing of nest failure. An environmental factor such as harassment of incubating cranes by black flies (Simulium spp.) may be responsible for widespread nest desertion

TEN-YEAR STATUS OF THE EASTERN MIGRATORY WHOOPING CRANE REINTRODUCTION

From 2001 to 2010, 132 costume-reared juvenile whooping cranes (Grus americana) were led by ultralight aircraft from Necedah National Wildlife Refuge (NWR) in central Wisconsin to the Gulf Coast of Florida on their first autumn migration (ultralight-led or UL), and 46 juveniles were released directly on Necedah NWR during autumn of the hatch year (direct autumn release or DAR). Return rate in spring was 90.5% for UL and 69.2% for DAR, the lower value of the latter attributable to 1 cohort with migration problems. Overall population survival 1 year and from 1 to 3 years post-release was 81% and 84%, respectively. Survival 1 year post-release was significantly different between UL (85.1%) and DAR (65.7%) cranes. Since summer 2008, DAR migration and wintering have improved, winter distribution of the population has changed, the migration route of the population has shifted westward, and number of yearlings summering in locations used during spring wandering has increased. Human avoidance problems resulted in 2 birds being removed from the population. As in earlier years, homing to the natal area and prolific pair formation continued (29 of 31 adult pairs have formed in the core reintroduction area), predation continued to be the primary cause of mortality, and parental desertion of nests, especially during the initial (primary) nesting period, continued. During 2005-2010, all 43 of these early nests failed; of 15 late nests or renests, chicks hatched from 8 nests, and 3 chicks fledged. As of 31 March 2011, the population contained a maximum 105 individuals (54 males and 51 females) including 20 adult pairs

THE ROLE OF RETRIEVAL AND TRANSLOCATION IN A REINTRODUCED POPULATION OF MIGRATORY WHOOPING CRANES

Beginning in 2001, a reintroduction project was initiated using captive-reared whooping cranes (Grus americana) to establish a migratory flock in eastern North America. From May 2003 to August 2008, 23 of these birds were retrieved and translocated in 15 separate events. These individuals consisted of 14 cranes that had been led to Florida by ultralight aircraft on their first autumn migration (UL) and 9 cranes that had been directly released in autumn in Wisconsin (DAR). Of 104 (86 UL and 18 DAR) reintroduced individuals that eventually departed from their release location, 22% were later retrieved 1-3 times. Lake Michigan posed an effective barrier to northward migrating yearlings, and 8 retrieval events were of birds in Lower Michigan or in other locations that were a direct result of the bird having been in Michigan during their yearling spring and summer. Three events involved DAR birds (n = 8) that were in inappropriate locations during their first autumn migration, and in another event 4 UL birds were translocated within Wisconsin because of inadequate human avoidance behavior. Nine yearlings (6 UL and 3 DAR) in Lower Michigan were not retrieved (retrievals were attempted for only 3 of the birds). The summer location of released birds influenced the location of return in future years. Concentration of this population in the core reintroduction area, where probability of pair formation and association with conspecifics was greatest, became a high project priority. Retrieval and translocation of yearlings to Wisconsin became a critical management tool in the reintroduction. With 1 exception, all translocated birds have successfully returned to the core reintroduction area by 2008, and several have paired and some nested

SURVIVAL, REPRODUCTION, AND MOVEMENTS OF MIGRATORY WHOOPING CRANES DURING THE FIRST SEVEN YEARS OF REINTRODUCTION

An effort to reintroduce a migratory population of whooping cranes (Grus americana) into eastern North America began in 2001. During 2001-2007, 125 juveniles were costume/isolation-reared and released: 106 were led by ultralight aircraft from Necedah National Wildlife Refuge (NWR), central Wisconsin, to Chassahowitzka NWR, central Gulf Coast of Florida, on their first autumn migration (ultralight-led or UL). The remaining 19 individuals were released directly on Necedah NWR during autumn of the hatch year (direct autumn release or DAR). Of 86 UL and 13 DAR cranes that completed their first spring migration, 72 (84%) and 5 (38%), respectively, returned unassisted as yearlings to central Wisconsin. Yearlings typically returned to Necedah NWR and then wandered to other spring locations, mainly in southern and eastern Wisconsin, but also to locations as far as 1,370 km distant. Most yearlings returned to central Wisconsin by early summer, especially males, and females associated with males. Lake Michigan posed an effective barrier to 16 yearlings that migrated too far eastward during spring migration. Some of these birds and others were retrieved and translocated. For UL cranes, 48% of returning bird-winters occurred in a primary wintering area within 88 km of the original release site and an additional 12% at a smaller area of concentration 82-103 km northward. Other UL and DAR cranes wintered at sites primarily in Florida, South Carolina, Tennessee, Alabama, or Indiana. Excluding 17 UL juveniles that died in a single weather-related event at the winter release site in 2007, 40 individuals (37% of those in the population) died during the first 7 years of the reintroduction. The primary cause was predation (minimally 50%). During 2005-2008, all 22 first nests with eggs failed. Of 2 renests during the same period, 2 chicks hatched from 1 nest and 1 chick fledged in 2006. Consistent nest failures were mainly synchronous and usually occurred on warm days. As of September 2008, the population contained a maximum 68 individuals (39 males and 29 females) including 12 adult pairs

TEN-YEAR STATUS OF THE EASTERN MIGRATORY WHOOPING CRANE REINTRODUCTION

From 2001 to 2010, 132 costume-reared juvenile whooping cranes (Grus americana) were led by ultralight aircraft from Necedah National Wildlife Refuge (NWR) in central Wisconsin to the Gulf Coast of Florida on their first autumn migration (ultralight-led or UL), and 46 juveniles were released directly on Necedah NWR during autumn of the hatch year (direct autumn release or DAR). Return rate in spring was 90.5% for UL and 69.2% for DAR, the lower value of the latter attributable to 1 cohort with migration problems. Overall population survival 1 year and from 1 to 3 years post-release was 81% and 84%, respectively. Survival 1 year post-release was significantly different between UL (85.1%) and DAR (65.7%) cranes. Since summer 2008, DAR migration and wintering have improved, winter distribution of the population has changed, the migration route of the population has shifted westward, and number of yearlings summering in locations used during spring wandering has increased. Human avoidance problems resulted in 2 birds being removed from the population. As in earlier years, homing to the natal area and prolific pair formation continued (29 of 31 adult pairs have formed in the core reintroduction area), predation continued to be the primary cause of mortality, and parental desertion of nests, especially during the initial (primary) nesting period, continued. During 2005-2010, all 43 of these early nests failed; of 15 late nests or renests, chicks hatched from 8 nests, and 3 chicks fledged. As of 31 March 2011, the population contained a maximum 105 individuals (54 males and 51 females) including 20 adult pairs

FIRST COHORT OF MIGRATORY WHOOPING CRANES REINTRODUCED TO EASTERN NORTH AMERICA: THE FIRST YEAR AFTER RELEASE

We describe the post-release movements and survival of the first cohort in the eastern migratory whooping crane (Grus americana) reintroduction from release the first winter through return the second winter. Six cranes were led behind ultralight aircraft from Necedah National Wildlife Refuge (NWR), Central Wisconsin, to Chassahowitzka NWR, Gulf Coast of Florida. After release in Florida, 1 of these cranes and another transported there by truck were killed by bobcats (Lynx rufus). The winter management protocol was modified and no further predation occurred. The 5 remaining cranes migrated unassisted back to Necedah NWR in spring, left the refuge during a spring wandering period, and then 4 returned to Necedah NWR to spend the summer. All 5 birds migrated back to Florida to winter, and 4 returned at least initially to Chassahowitzka NWR or adjacent salt marsh before 3 dispersed to suitable habitat inland. One yearling remained at Chassahowitzka NWR with the newly released juveniles from the second year’s release. Of the other 4 birds, 2 wintered separately with sandhill cranes (G. canadensis) in northern Florida, and 2 wintered as a pair on ranchland 62 km from the original winter release site. After the bobcat predation problem was solved, the subsequent survival, migration, summering, and wintering of these reintroduced whooping cranes were favorable for a successful reintroduction

Wing Abnormality in a Wild-Hatched Whooping Crane () Chick from the Nonmigratory Population in Louisiana, USA

We describe a wing abnormality in a wild-hatched Whooping Crane () chick from the reintroduced Louisiana, US nonmigratory population. Despite its seemingly compromised flight ability, the chick fledged, reached independence, and lived until 13 mo of age. Necropsy revealed an axial malunion near the left carpus likely resulting from trauma