08 February 2013

Results of Sandhill Waterbird Surveys Released

Prepared for the Grant County News. Publication pending.

Birds that rely on edible fish in numerous lakes among the Sand Hills, do not pose a threat to the area's sport fishery, according to a report released mid-January by the Nebraska Game and Parks Commission.

There had been concern that flocks of fish-eating Double-crested Cormorant, American White Pelican and Western Grebe might be a negative influence, so a research study was done during August to October, 2012 to determine extent and numbers.

Two routes were surveyed once in August, September and October.

A western route included Lake McConaughy, Crescent Lake National Wildlife Refuge, and other lake settings in northern Garden county, southern Sheridan county, southwest Cherry county and Grant county.

An eastern route included Calamus Reservoir, the Lakeland district in southwest Brown county, Valentine National Wildlife Refuge and other water settings in eastern Cherry county, along with a few significant lakes further east, including Swan Lake, west of Chambers, Holt county.

Overall, 406 lakes were visited, according to the Commission report, with 144 lakes surveyed three times.

There were only a few large gatherings of cormorants on natural lakes within the sandhills, according to the agency report, available online, by authors Lauren R. Dinan and Joel G. Jorgensen, manager of the nongame bird program.

One exception was Calamus Reservoir, where many of these birds gathered during the migratory season, especially in October, when the count tally was 7500. It is apparently is "an important staging area." The birds feed on gizzard shad, according to fisheries division personnel of the agency.

Other lakes where larger numbers of cormorants occurred during the surveys were Crescent Lake, and Goose Lake nearby on the federal refuge. Goose Lake had a nesting colony during the summer, so it was obviously an attractive place for these birds.

Pelicans and grebes were present at less than 20% of the lakes visited, and not to any extent that would have a significant impact upon the fish population.

Neither of these three species was present at many of the lakes at the time they were surveyed.

Calamus Reservoir was also notable for the occurrence of a large numbers of pelicans, the report indicates. This big, white bird also occurred at other lakes, with numbers from 200-500.

Some of the lakes where larger numbers of pelicans were noted, included Avocet WMA east of Hyannis (200 on September survey) and Little Hay Lake (100 in August), up north in Cherry county.

The greatest number of counted grebes was at Lake McConaughy, especially in September. Western Grebes, along with the less frequent Clark's Grebe, are known to prominently occur on this Platte River reservoir, with 11,200 denoted during the visit by NGPC biologists, according to the report. They were also prominent at Merritt Reservoir in October, and, during the same month, at Big Alkali Lake by Valentine NWR, and at Crescent and Blue lakes in Garden county.

The report did indicate that cormorants could be problematic, since 102 of these birds "were eliminated" at the Calamus Fish Hatchery between mid-August and the end of October, 2012, the report said.

During this project, specific protocols were used to provide consistent results, for accurate and statistically comparable purposes. The report document has the resultant graphs and figures from analysis of collected details.

Though focused on their task, Dinan also expressed that the surveys provided an opportunity to "get out of the office and appreciate" the outdoors of western Nebraska. "The sandhills are definitely unique and beautiful," she said. "I especially appreciated the opportunities to visit the various lakes, and to observe the birds."

The results of this study, in addition to its primary purpose, is uniquely important documentation of overall occurrence and distribution for three species, in an area where bird surveys don't occur very often.