COORDINATED SPRING SURVEY OF
MID-CONTINENT SANDHILL CRANES
2005
2005
COORDINATED SPRING SURVEY OF MID-CONTINENT SANDHILL CRANES
2005 TOTAL: 530,600
2005 AERIAL TRANSECT: 491,900
THREE-YEAR AVERAGE (2003-05): 422,100
SURVEY DATES: 5 - 25 March 2005
SURVEY PERSONNEL:
Aerial Survey
Observer/pilot: John Solberg, USFWS, DMBM, Bismarck, ND
Observer: Jeff Drahota, USFWS, Rainwater Basin WMD, Kearney, NE
Photographer: Rich Walters, NGPC, Kearney, NE
Ground Surveys (State Coordinators)
North Dakota: Mike Szymanski, NDGFD, Bismarck, ND
South Dakota: Spencer Vaa, SDGFP, Brookings, SD
Nebraska: Mark Vrtiska, NGPC, Lincoln, NE
Kansas: Helen Hands, KDWP, Great Bend, KS
Texas: Jay Roberson, TPWD, Austin, TX
ABSTRACT: The aerial transect portion of the coordinated spring survey of mid-continent sandhill
cranes was conducted on 23 March in Nebraska’s Platte and North Platte River valleys. The 2005
photo corrected aerial estimate was 491,900 birds. Outside the traditional aerial transect portion,
observers utilized both ground and air coverage during the period 5 – 25 March. From this region,
observers in the Official Survey Area (OSA) of Nebraska, Kansas, and Texas reported an additional
38,700 cranes. The 2005 total estimate (530,600) increased 18% since 2004 and is the fourth highest
in twenty-four years of comparable figures. The current three-year average (2003 - 2005), from
photo corrected aerial transects only, is 422,100.
METHODS: The annual target date for the coordinated survey is the 4th Tuesday of March. Survey
coverage in 2005 was similar to 2004 and included changes adopted by the Central Management
Unit Technical Committee (CMU) in 1985. The “traditional” aerial portion of the survey utilizes an
ocular transect design with a sampling rate of approximately twenty-five percent. Sub-sampling
crane flocks, using 35 mm oblique photography, allows determination of observer specific
estimation correction factors which are applied to estimates from the aerial transects. Efforts outside
the region of the traditional aerial transects are directed by state coordinators. Using a combination
of ground and aerial coverage, these efforts focus in areas of traditional crane use/occurrence.
Observations recorded outside the aerial transect region are not photo corrected. Specific details
regarding personnel, photography, habitat, and weather conditions are on file in the Bismarck office
of the USFWS.
RESULTS: The aerial transect component of the 2005 survey was conducted on 3/23, one day later
than scheduled (weather delay). Concurrently, USGS field researchers reported that 90% (38 of 42)
of their VHF radio marked cranes were present in the Platte River Valley (D. A. Brandt, USGS,
pers. comm.). The 2005 total estimate of mid-continent sandhill cranes is 530,600 (Table 1), which
includes 491,900 birds from aerial transects (Tables 2 and 3), and 38,700 cranes from other regions
in the OSA. Correction factors, applied to aerial estimates, were calculated from photographs of 56
unique flocks (Drahota 23, Solberg 33). Observer effort in the 2005 survey is presented in Table 4.
The 2005 index increased 18% from the 2004 figure and is the fourth highest of comparable record
(24 years). The current three-year average (2003-2005), based on the photo-corrected Nebraska
aerial portion, is 422,100 (Figure 1) and is within the management range (343,000 - 465,000)
established by the CMU (Management Guidelines for Mid-Continent Sandhill Cranes, revised
March 1993).
Appreciation is expressed to all coordinators, observers, and participants who assisted in the 2005
survey. Two long time contributors, Dr. Douglas Johnson (Northern Prairie Wildlife Research
Center, USGS) for his statistical analysis and Mr. John Steiner (Jamestown, ND) for his photo
processing and interpretation, continued their able assistance and support in completing the final
report.
John W. Solberg
February 2006
Reference:
Benning, D. S. and D. H. Johnson. 1987. Recent improvements to sandhill crane surveys in
Nebraska’s Central Platte Valley. pp 10 – 16 in J. C. Lewis (ed.), Proc. 1985 Crane Workshop,
Platte River Whooping Crane Habitat Maint. Trust, Grand Island, NE.
Table 1. Distribution of Sandhill Cranes within the Mid-Continent region during the coordinated spring survey, 1974-2005 (rounded to nearest 100).
Date ND 5 SD 5 NEBRASKA KS TX TOTAL OK 6 NM 6 CO 6 TOTAL
Central Platte Valley 1 Other (OSA) of all sources (excluding ND & SD)
when added to the following:
Ocular trans. Vertical Ocular Ocular Vertical
Ocular Ocular w/photo photo Ocular transect transect photo
cruise transect correction transect cruise uncorrected photo corrected transect
3/24-31/74 0 0 162,600(92%) 4 - - - 9,000 1,900 3,200 - 400 0 0 177,100 - - -
3/25-30/75 0 0 223,600(98%) - - - 2,300 900 Tr - 100 100 500 227,500 - - -
3/22-26/76 - 2 0 147,500(97%) - - - 2,800 300 800 - 100 1,000 0 152,500 - - -
3/13-23/77 0 300 173,400(79%) - - - 1,100 1,600 30,700 - 400 12,500 0 220,000 - - -
3/20-24/78 - 0 149,800(94%) 188,600(95%) - - 2,200 700 4,900 - 0 2,300 0 159,900 198,700 - -
3/20-29/79 0 0 - 203,600(97%) - - 2,600 1,100 0 - 1,500 0 500 - 209,300 - -
3/24-4/15/80 Tr 3 - 223,400(95%) 254,400(96%) - - 5,000 4,100 1,400 - 100 500 0 234,500 265,500 - -
3/22-28/81 0 0 - 248,900(86%) - - 8,300 11,200 21,800 - 0 0 200 - 290,400 - -
3/22-27/82 0 Tr - 348,000(95%) 417,300(95%) 490,100(96%) 7,100 2,000 7,800 - 0 100 2,800 - 367,800 437,100 509,900
3/25-26/83 0 0 - 306,300(96%) 343,400(97%) - 4,100 200 7,000 - 200 Tr 0 - 317,800 354,900 -
3/25-30/84 0 Tr - 222,700(91%) 261,800(93%) - 18,100 900 800 - 1,100 Tr 0 - 243,600 282,700 -
3/25-26/85 - - - 378,100(96%) 514,800(97%) - 11,500 3,000 1,200 530,500 - - - - 393,800 530,500 -
3/25-26/86 Tr Tr - 317,000(99%) 353,000(99%) - 1,000 200 2,100 356,300 - - - - 320,300 356,300 -
3/24-26/87 0 0 - 383,600(100%) 416,100(100%) - 0 Tr 400 416,500 - - - - 384,000 416,500 -
3/21-25/88 0 0 - 386,900(98%) 463,500(98%) - 0 0 7,700 471,200 - - - - 394,600 471,200 -
3/28-29/89 0 200 - 391,400(100%) 392,000(100%) - 100 1,000 800 393,900 - - - - 393,300 393,900 -
3/27-28/90 Tr Tr - 386,000(94%) 412,200(94%) - 11,000 5,200 10,300 438,700 - - - - 412,500 438,700 -
3/25-26/91 0 200 - 297,800(100%) 340,600(100%) - 100 800 200 341,700 - - - - 298,900 341,700 -
3/19-25/92 200 Tr - 257,700(95%) 406,500(97%) - 12,200 300 1,100 420,100 - - - - 271,300 420,100 -
3/23-24/93 0 100 - 253,800(79%) 378,900(85%) - 16,800 37,700 13,500 446,900 - - - - 321,800 446,900 -
3/20-22/94 400 0 - 395,500(96%) 477,200(96%) - 14,600 0 0 491,800 - - 2,400 - 412,500 494,200 -
3/28-30/95 200 0 - 273,400(88%) 326,200(90%) - 30,400 0 0 356,600 - - 6,700 - 310,500 363,300 -
3/25-26/96 0 0 - 318,900(96%) 520,000(98%) - 7,600 0 0 527,600 - - 3,900 - 330,400 531,500 -
3/20-26/97 Tr Tr - 350,900(96%) 534,600(97%) - 16,200 100 0 550,900 - - - - 367,200 550,900 -
3/24-26/98 0 Tr - 337,200(96%) 530,800(97%) - 13,600 100 0 544,500 - - - - 350,900 544,500 -
3/22-25/99 0 500 - 219,800(68%) 284,900(73%) - 3,500 100,000 0 388,400 - - - - 323,300 388,400 -
3/10-29/00 100 800 - 484,600(92%) 490,100(92%) - 16,900 26,100 500 533,600 - - - - 528,100 533,600 -
3/25-27/01 0 Tr - 387,300(87%) 413,500(88%) - 10,500 42,300 3,500 469,800 - - - - 443,600 469,800 -
3/25-27/02 Tr 0 - 309,000(90%) 315,000(90%) - 17,100 15,100 1,200 348,400 5,800 - - - 348,200 354,200 -
3/22-27/03 Tr 400 - 300,900(90%) 348,000(91%) - 24,800 4,100 3,800 380,700 - - - - 333,600 380,700 -
3/22-25/04 50 600 - 365,400(94%) 426,500(95%) - 17,700 1,200 2,200 447,600 100 - - - 386,600 447,700 -
3/5 - 25/05 Tr 500 - 412,300(93%) 491,900(93%) - 27,100 2,900 8,700 530,600 2,600 - - - 453,600 533,200 -
1 Utilizing various survey techniques within Nebraska's Central Platte Valley.
2 No survey.
3 Less than 50.
4 Percent of total M-C population index.
5 Crane sightings for North and South Dakota from 1985 and later are noted for over flight monitoring purposes and are not included in totals.
6 OK, NM, CO were eliminated from the Official Survey Area in 1985 by the Central Flyway CMU; crane sightings are noted for informational purposes only.
Table 2. Results of ocular transect survey for Mid-Continent Sandhill Cranes in the
central Platte Valley of Nebraska during the coordinated spring surveys.
YEAR Population Index Standard Error
1978 188,582 ± 23,948 (± 12.7%)
1979 203,574 ± 24,968 (± 12.1%)
1980 254,417 ± 51,738 (± 20.3%)
1981 248,882 ± 31,957 (± 12.8%)
1982 347,996 ± 33,353 (± 9.6%)
1983 306,316 ± 21,257 (± 6.9%)
1984 222,710 ± 17,466 (± 7.8%)
1985 378,127 ± 34,230 (± 9.1%)
1986 317,025 ± 32,461 (± 10.2%)
1987 383,581 ± 53,508 (± 13.9%)
1988 386,853 ± 35,775 (± 9.2%)
1989 391,353 ± 44,066 (± 11.2%)
1990 385,950 ± 40,585 (± 10.5%)
1991 297,831 ± 27,551 (± 9.2%)
1992 257,709 ± 24,551 (± 9.5%)
1993 253,799 ± 29,896 (± 11.2%)
1994 395,543 ± 40,430 (± 10.2%)
1995 273,376 ± 30,316 (± 11.1%)
1996 318,514 ± 36,182 (± 11.3%)
1997 350,932 ± 58,925 (± 16.7%)
1998 337,203 ± 39,505 (± 11.7%)
1999 219,794 ± 32,164 (± 14.6%)
2000 484,585 ± 57,598 (± 11.9%)
2001 387,336 ± 47,679 (± 12.3%)
2002 309,029 ± 34,399 (± 11.1%)
2003 300,918 ± 32,869 (± 10.9%)
2004 365,370 ± 31,001 (± 8.5%)
2005 412,285 ± 32,482 (± 7.8%)
Table 3. Results of ocular transect survey with photo correction fo for Mid-Continent Sandhill Cranes
in the central Platte Valley of Nebraska during the coordinanted spring surveys.
YEAR Population Index Standard Error
1982 417,263 ± 42,331 (± 10.1%)
1983 343,378 ± 31,674 (± 9.2%)
1984 261,802 ± 24,198 (± 9.2%)
1985 514,763 ± 49,650 (± 9.6%)
1986 353,040 ± 37,340 (± 10.6%)
1987 416,058 ± 65,588 (± 15.7%)
1988 463,457 ± 53,213 (± 11.4%)
1989 391,995 ± 51,349 (± 13.0%)
1990 412,154 ± 50,496 (± 12.2%)
1991 340,645 ± 33,897 (± 10.0%)
1992 406,457 ± 50,644 (± 12.4%)
1993 378,883 ± 50,454 (± 13.3%)
1994 477,215 ± 50,910 (± 10.7%)
1995 326,181 ± 35,256 (± 10.8%)
1996 519,984 ± 62,582 (± 12.0%)
1997 534,630 ± 86,889 (± 16.2%)
1998 530,848 ± 79,164 (± 14.9%)
1999 284,858 ± 35,599 (± 12.5%)
2000 490,118 ± 71,754 (± 14.6%)
2001 413,498 ± 64,221 (± 15.5%)
2002 315,044 ± 42,218 (± 13.4%)
2003 348,023 ± 41,263 (± 11.9%)
2004 426,534 ± 43,337 (± 10.2%)
2005 491,915 ± 47,392 (± 9.6%)
Table 4. Coordinated spring Mid-Continent Sandhill Crane survey effort by state - 2005.
State Date Coverage Means Effort Observer Affiliation
Aircraft Ground (Miles) Federal State Volunteer
Air/Gnd.
ND* 17 - 22 March 2005 - 11 - /900 2 10 -
SD* 5 - 22 March 2005 - ? - / ? 12 8 5
NE 22 - 23 March 2005 2 15 1200/1400 3 17 -
KS 21 - 25 March 2005 - 11 - / 300 1 8 2
TX 22 March 2005 - 10 - /1300 3 6 1
Total 2 47 1200/3900 21 49 8
* Monitors for over flights on or prior to scheduled survey date.
Figure 1. Annual and three-year average photo-corrected ocular transect spring population
indices and population objective thresholds for Mid-Continent sandhill cranes.
200
250
300
350
400
450
500
550
600
1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005
Year
Sandhill Crane (Thousands)
Annual Index
3-Year Avg
Thresholds