Abundance and trend of waterbirds on Alaska’s Yukon-Kuskokwim Delta coast based on 1988 to 2012 aerial surveys

Metadata Updated: October 9, 2019

We summarize 1988 to 2012 (no survey in 2011) aerial survey waterbird sightings that index the abundance and trend of populations in the Yukon-Kuskokwim delta coastal zone. The threatened spectacled eider (Somateria fischeri) population index for 2012 was 6,138 birds. Traditionally, a visibility correction factor of 3.58 has been applied for spectacled eiders yielding a population estimate of 21,974 which was 85% above its 1988-2012 long-term average (LTA) size. However, we calculated a new estimate of visibility rate for spectacled eiders in 2010 using the ratio of the aerial index of indicated breeding birds to the estimated population of nests (Fischer et al. 2010). The ratio was 0.425 nests per aerial indicated pair or, expressed as the inverse, 2.351 birds (minimum of 2 birds per nest) per aerial index. Using this correction, the population estimate for spectacled eiders was 14,442 breeding birds. In 2012 the three most numerous waterfowl species were northern pintail (Anas acuta) with a visibility-corrected estimate of 186,986 birds, greater scaup (Aythya marila) with 70,955 birds, and green-winged teal (Anas crecca) at 23,558 birds. The estimated population sizes for species of special interest were 4,174 common eiders (Somateria mollissima), 8,963 long-tailed ducks (Clangula hyamelis), 10,408 black scoters (Melanitta nigra), and 860 red-throated loons (Gavia stellata). The estimated number of pintails was 23% above the LTA. Numbers of long-tailed ducks, northern shovelers, red-breasted mergansers, and red-throated loons were substantially below their LTAs. Of the non-waterfowl species in 2012, glaucous gulls (Larus hyperboreus) were most numerous with an estimated 40,744 birds (7%above LTA), followed by 36,224 (+86%) Sabine’s gulls and 22,700 (+64%) mew gulls. The estimated population of Arctic terns was 29,427 (+45%). Pacific loons (Gavia pacifica) were estimated at 13,946 birds (-15%). Twenty-five year trends based on log-linear regression showed significant population increases (p<0.10) for greater scaup, spectacled eider, common eider, redbreasted merganser (Mergus serrator), Sabine’s gull (Xema sabini), mew gull (Larus canus), and arctic tern (Sterna paradisaea). Populations declined for American wigeon (Anas americana), canvasback (Aythya valisineria), and jaegers (Stercorarius spp.). Previous analysis showed a strong correlation between the thaw-degree-day index of spring warming temperatures and average cackling goose (Branta hutchinsii minima) clutch initiation date. We used this relationship to predict an appropriate start date for the 2012 survey consistent with average survey timing of the last several years. We began flights on June 3, nine days after predicted average nest initiation of 27 May. Later examination of nesting data showed the average cackling goose initiation date was 2 June (Fischer et al. 2013). Therefore, the 2012 survey started about 7 days earlier in timing relative to average nest initiation compared to recent years. We continued to compile individual geographic locations for sightings of 21 major species of waterbirds and now have over 139,000 bird locations in a geographic information system useful for research and management.

Access & Use Information

Restricted: This dataset can only be accessed or used under certain conditions. License: No license information was provided. If this work was prepared by an officer or employee of the United States government as part of that person's official duties it is considered a U.S. Government Work.
The information resource is proprietary and/or copyrighted. Access to this information by the public is very limited. Please contact the associated Point of Contact regarding additional use constraints and requirements for obtaining the information.

Downloads & Resources

References

https://ecos.fws.gov/ServCat/Reference/Profile/66711

References

https://ecos.fws.gov/ServCat/Reference/Profile/66711

Dates

Metadata Created Date April 30, 2019
Metadata Updated Date October 9, 2019

Metadata Source

Harvested from DOI CKAN Harvest Source

Additional Metadata

Resource Type Dataset
Metadata Created Date April 30, 2019
Metadata Updated Date October 9, 2019
Publisher Fish and Wildlife Service
Unique Identifier FWS_ServCat_66711
Maintainer
Brent Frakes
Maintainer Email
Public Access Level restricted public
Bureau Code 010:18
Metadata Context https://project-open-data.cio.gov/v1.1/schema/catalog.jsonld
Metadata Catalog ID C:\Program Files (x86)\FWS\DataStore\Application\OpenData\FWS_ServCat_v1_1.json
Schema Version https://project-open-data.cio.gov/v1.1/schema
Catalog Describedby https://project-open-data.cio.gov/v1.1/schema/catalog.json
Extras Rollup {"harvest_source_id": "34ce571b-cb98-4e0b-979f-30f9ecc452c5", "issued": "2013-07-08", "resource-type": "Dataset", "references": "\"https://ecos.fws.gov/ServCat/Reference/Profile/66711\"", "source_hash": "b38b86ac30ead246f5b04769867a38c611bf572e", "accessLevel": "restricted public", "theme": "\"Unpublished Report\"", "spatial": "-167.852325,59.6325264,-159.136978,63.4883766", "catalog_conformsTo": "https://project-open-data.cio.gov/v1.1/schema", "catalog_@context": "https://project-open-data.cio.gov/v1.1/schema/catalog.jsonld", "catalog_describedBy": "https://project-open-data.cio.gov/v1.1/schema/catalog.json", "harvest_source_title": "DOI CKAN Harvest Source", "source_schema_version": "1.1", "programCode": "010:094", "010:028", "bureauCode": "010:18", "landingPage": "https://ecos.fws.gov/ServCat/Reference/Profile/66711", "harvest_object_id": "5c27101b-d344-45b9-b634-85328d92ccde", "publisher": "Fish and Wildlife Service", "rights": "The information resource is proprietary and/or copyrighted. Access to this information by the public is very limited. Please contact the associated Point of Contact regarding additional use constraints and requirements for obtaining the information.", "modified": "2013-07-08", "source_datajson_identifier": "true", "catalog_@id": "C:\\Program Files (x86)\\FWS\\DataStore\\Application\\OpenData\\FWS_ServCat_v1_1.json", "identifier": "FWS_ServCat_66711"}
Harvest Object Id 04ec1189-d6a7-42da-8e33-d6669c8e1ff5
Harvest Source Id 34ce571b-cb98-4e0b-979f-30f9ecc452c5
Harvest Source Title DOI CKAN Harvest Source
Data First Published 2013-07-08
Homepage URL https://ecos.fws.gov/ServCat/Reference/Profile/66711
Data Last Modified 2013-07-08
Program Code 010:094, 010:028
Related Documents "https://ecos.fws.gov/ServCat/Reference/Profile/66711"
Rights The information resource is proprietary and/or copyrighted. Access to this information by the public is very limited. Please contact the associated Point of Contact regarding additional use constraints and requirements for obtaining the information.
Source Datajson Identifier true
Source Hash b38b86ac30ead246f5b04769867a38c611bf572e
Source Schema Version 1.1
Spatial -167.852325,59.6325264,-159.136978,63.4883766
Category "Unpublished Report"

Didn't find what you're looking for? Suggest a dataset here.