Recruitment in Rocky Mountain Greater Sandhill Cranes and Comparison with Other Crane Populations

Drewien, Roderick C.; Brown, Wendy M.; Kendall, William L.

doi:10.2307/3808948

Cited by 38 publications

(60 citation statements)

References 24 publications

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“…Frequencies in Zhigatse Prefecture during our three years of surveys ranged from 8.2-11.3 chicks/100 cranes. Among populations of the well-studied Sandhill Crane (Grus canadensis) in North America, ~6 chicks/100 cranes approximates the lowest documented mortality rates (Drewien et al, 1995), suggesting that the population in Zhigatse Prefecture is stable, if not increasing. Long-term monitoring of Black-necked Cranes will be critical to obtain an accurate picture of the population trend.…”

Section: Discussionmentioning

confidence: 99%

Number and distribution of Black-necked Cranes wintering in Zhigatse Prefecture, Tibet

Bishop¹,

Tsamchu²,

Li³

2012

Chinese Birds

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We surveyed all known wintering areas of the Black-necked Crane (Grus nigricollis) in Zhigatse Prefecture of the Tibet Autonomous Region during three winters. Our surveys confirm that Zhigatse Prefecture is the most important wintering area for the species, accounting in some years for as much as 39% of the estimated world population. Counts ranged from a high of 4240 cranes in January 2007 to a low of 2636 in February 2009. Chick recruitment (chicks/100 cranes) ranged from 8.2 (January 2010) to 11.3 (January 2007). The highest concentration of cranes during all three surveys occurred on the 60 km stretch of the Yarlung Tsangpo (River) between Lhaze and Phuntsoling. To evaluate potential impacts of the Xietongmen Copper Mine, we monitored wintering crane numbers prior to mine installation in an intensive study area located between the Shab Chu Valley and the city of Zhigatse. Our surveys recorded on average 820 ± 83 cranes (SE; n = 8) in this area. With the installation of the mine at a location ~50 km west of Zhigatse, increased traffic and development on the north side of the Yarlung River will likely result in a shift in crane distribution away from the north side, to nearby suitable habitats. Based on our survey results, we recommend three areas hosting high numbers of cranes in the vicinity of the mine be added to the Yarlung Tsangpo Middle Reaches Blacknecked Crane Nature Reserve. These areas are Nierixiong and Jiaqingze Villages in Nierixiong Xiang and the Shab Chu Valley.

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Section: Discussionmentioning

confidence: 99%

Number and distribution of Black-necked Cranes wintering in Zhigatse Prefecture, Tibet

Bishop¹,

Tsamchu²,

Li³

2012

Chinese Birds

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“…The MCP also is widely dispersed during the remainder of spring migration, during fall migration, and on their wintering grounds , further limiting potential for obtaining reliable estimates of size of the MCP outside of Nebraska. Sandhill cranes have the lowest annual recruitment rate of any hunted avian species in North America (Drewien et al 1995) so greater precision is required for estimates of population size before making decisions affecting size of annual MCP harvest than is necessary for other game birds.…”

Section: Nocturnal Roosting Habitat In Cprvmentioning

confidence: 99%

Spring migration ecology of the mid‐continent sandhill crane population with an emphasis on use of the Central Platte River Valley, Nebraska

Krapu

Brandt

Kinzel

et al. 2014

Wildlife Monographs

109

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We conducted a 10-year study (1998)(1999)(2000)(2001)(2002)(2003)(2004)(2005)(2006)(2007) of the Mid-Continent Population (MCP) of sandhill cranes (Grus canadensis) to identify spring-migration corridors, locations of major stopovers, and migration chronology by crane breeding affiliation (western Alaska-Siberia [WA-S], northern Canada-Nunavut [NC-N], west-central Canada-Alaska [WC-A], and east-central Canada-Minnesota [EC-M]). In the Central Platte River Valley (CPRV) of Nebraska, we evaluated factors influencing staging chronology, food habits, fat storage, and habitat use of sandhill cranes. We compared our findings to results from the Platte River Ecology Study conducted during [1978][1979][1980]. We determined spring migration corridors used by the breeding affiliations (designated subpopulations for management purposes) by monitoring 169 cranes marked with platform transmitter terminals (PTTs). We also marked and monitored 456 cranes in the CPRV with very high frequency (VHF) transmitters to evaluate length and pattern of stay, habitat use, and movements. An estimated 42% and 58% of cranes staging in the CPRV were greater sandhill cranes (G. c. tabida) and lesser sandhill cranes (G. c. canadensis), and they stayed for an average of 20 and 25 days (2000)(2001)(2002)(2003)(2004)(2005)(2006)(2007), respectively. Cranes from the WA-S, NC-N, WC-A, and EC-M affiliations spent an average of 72, 77, 52, and 53 days, respectively, in spring migration of which 28, 23, 24, and 18 days occurred in the CPRV. The majority of the WA-S subpopulation settled in the CPRV apparently because of inadequate habitat to support more birds upstream, although WA-S cranes accounted for >90% of birds staging in the North Platte River Valley. Crane staging duration in the CPRV was negatively correlated with arrival dates; 92% of cranes stayed >7 days. A program of annual mechanical removal of mature stands of woody growth and seedlings that began in the early 1980s primarily in the main channel of the Platte River has allowed distribution of crane roosts to remain relatively stable over the past 2 decades. Most cranes returned to nocturnal roost sites used in previous years. Corn residues dominated the diet of sandhill cranes in the CPRV, as in the 1970s, despite a marked decline in standing crop of corn residues. Only 14% (10 of 74) of PTT-marked migrant cranes stayed at stopovers for !5 days before arriving in the CPRV, which limited the contribution of sites south of the CPRV for fat accumulation needed for migration and reproduction. Body masses of cranes (after adjusting for body size [an index of fat]) at arrival in the CPRV varied widely among years (1998)(1999)(2000)(2001)(2002)(2003)(2004)(2005)(2006), indicating the importance of maintaining productive habitats on the wintering grounds to condition cranes for migration and reproduction. Average rates of fat gain by adult females while in the CPRV remained similar from 1978-1979 to 1998-1999 but declined among males. Distances cranes flew to feeding grounds in the C...

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“…Percentage of juveniles in the RMP in autumn averaged 7. 7% during 19727% during -20017% during (Sharp et al 2002, the lowest production rate recorded for any hunted avian species in North America (Drewien et al 1995). Although annual variation in production has been attributed to weather, availability of food and water, and predation on the breeding ground (Drewien et al 1995), little published data are available to assess the influence of such factors on nest or chick survival.…”

mentioning

confidence: 99%

“…Indices of the fall population indicate that the size of the RMP has been relatively stable since 1995 (Sharp et al 2002), but there is concern that recruitment and breeding populations may have declined (Drewien et al 1995). Percentage of juveniles in the RMP in autumn averaged 7.…”

mentioning

confidence: 99%

Sandhill Crane Abundance and Nesting Ecology at Grays Lake, Idaho

Austin¹,

Henry²,

Ball³

2007

J Wildl Manag

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: We examined population size and factors influencing nest survival of greater sandhill cranes (Grus canadensis tabida) at Grays Lake National Wildlife Refuge, Idaho, USA, during 1997–2000. Average local population of cranes from late April to early May, 1998–2000, was 735 cranes, 34% higher than that reported for May 1970–1971. We estimated 228 (SE = 30) nests in the basin core (excluding renests), 14% higher than a 1971 estimate. Apparent nest success in our study (x̄ = 60%, n = 519 nests) was lower than reported for Grays Lake 30–50 years earlier. Daily survival rates (DSRs) of all nests averaged 0.9707 (41.2%). The best model explaining nest survival included year and water depth and their interaction. Nest survival was highest (DSR = 0.9827) in 1998 compared with other years (0.9698‐0.9707). Nest survival changed little relative to water depth in 1998, when flooding was extensive and alternative prey (microtines) irrupted, but declined markedly with lower water levels in 2000, the driest year studied. Hypotheses relating nest survival to vegetation height, land use (idle, summer grazing, fall grazing), and date were not supported. In a before‐after‐control‐impact design using 12 experimental fields, nest survival differed among years but not among management treatments (idle, fall graze, fall burn, and summer—graze—idle rotation), nor was there an interaction between year and treatments. However, DSRs in fall‐burn fields declined from 0.9781 in 1997–1998 to 0.9503 in 1999–2000 (posttreatment). Changes in the predator community have likely contributed to declines in nest success since the 1950s and 1970s. Our results did not support earlier concerns about effects of habitat management practices on crane productivity. Nest survival could best be enhanced by managing spring water levels. Managers should continue censuses during late April to evaluate long‐term relationships to habitat conditions and management.

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Recruitment in Rocky Mountain Greater Sandhill Cranes and Comparison with Other Crane Populations

Cited by 38 publications

References 24 publications

Number and distribution of Black-necked Cranes wintering in Zhigatse Prefecture, Tibet

Number and distribution of Black-necked Cranes wintering in Zhigatse Prefecture, Tibet

Spring migration ecology of the mid‐continent sandhill crane population with an emphasis on use of the Central Platte River Valley, Nebraska

Sandhill Crane Abundance and Nesting Ecology at Grays Lake, Idaho

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