Derrick Lake, Malheur National Wildlife Refuge

Survey Citation:
Ivey, G. 2006. Atlases of waterbird nesting sites for California, Idaho, Oregon and Washington. Region 1 Non Game Program, U.S. Fish and Wildlife Service, Portland, Oregon.

• Type
  shore; air
• Time period
  1980, 21 July 1994
• Source
  Database
• Both Western and Clarks?
  N

Count Type	Range	Max	Year
Max Adults	1 to 100	50	1980
Most Recent Adults	1 to 100	20	1994
Max Nests	1 to 100	10	1994
Most Recent Nests	1 to 100	10	1994
Max Chicks	N/A	N/A	N/A
Most Recent Chicks	N/A	N/A	N/A

Comments:

Actual counts of birds in 1980 was 30 then observer adjusted pair numbers by the assumed visibility factor for 50 adults. Assuming date of 1 January 1980 is not right and just means 1980. In 1994, 10 was the actual nest count number which was doubled to estimate number of breeding birds.

Survey Citation:
Ivey, G., Western grebe colony locations and nest estimates, Harney Basin, Oregon.

• Time period
  1989, 1994
• Source
  Database
• Both Western and Clarks?
  N

Count Type	Range	Max	Year
Max Adults	1 to 100	presence	1989, 1994
Most Recent Adults	1 to 100	presence	1989, 1994
Max Nests	1 to 100	10-12	1989, 1994
Most Recent Nests	1 to 100	10-12	1994
Max Chicks	N/A	N/A	N/A
Most Recent Chicks	N/A	N/A	N/A

Comments:

Excel spreadsheet of Western grebe colony locations and nest estimates in Harney Basin during Ivey's time as a biologist at Malheur NWR. Adult count numbers not provided, entered as closest bin estimate for indexing. Compiled observations in the marshes at or near Derrick Lake.