Statement_of_Work_1.pdf

US Geological Survey-Alaska Science Center Statement of Work

I. GENERAL INFORMATION

Introduction

The US Geological Survey (USGS) is seeking detailed information on the abundance and distribution of brood-rearing Pacific Black Brant (Branta bernicla nigricans) and Lesser Snow Geese (Anser caerulescens caerulescens) on the Colville River Delta (CRD), Alaska. To meet this information need, the contractor will conduct fixed-wing aerial photo-surveys for both species in July/August 2026, covering the entire CRD. The contractor will summarize survey results and deliver a final report detailing the total numbers and distribution of adult and juvenile geese by the end of December 2026.

Background

The CRD is an important nesting area on the Arctic Coastal Plain for snow geese and black brant, two goose species that are popular with both sport and subsistence hunters. Between 2005 and 2023, the number of brood-rearing Brant on the CRD varied between about 500 and 3,000 adults annually, whereas the number of brood-rearing Snow Geese increased from fewer than 500 adults to estimates of over 36,000 adults during the same period, based on past surveys.

There is a growing need to understand how local increases in snow goose density affect nesting brant, and to assess the contributions of Arctic brant populations to their overall population status, because the primary nesting population for black brant in the Yukon-Kuskokwim Delta is in steep decline (Sedinger et al. 2019; Leach et al. 2017). In recognition of this need, the Arctic Goose Joint Venture (AGJV) and the Pacific Flyway Council have identified Western Arctic snow geese and brant as high-priority populations that require up-to-date estimation of population trends and assessment of the relationships between snow goose population density and grazing pressure on their shared habitat. USGS personnel have conducted ongoing ground studies of nesting and feeding ecology, habitat use, population dynamics, and a variety of life history attributes since 2011 (Ruthrauff et al. 2021), but past brood-rearing surveys represent the longest and most consistent record of population changes in the study area.

Scope

The general purpose of this contract is to conduct a complete census of adult and juvenile black brant throughout the Colville River Delta area of Alaska, and a representative survey of adult and juvenile snow geese covering 50% of the same study area. These surveys must be conducted in late July or early August 2026, during a period after all nests have hatched, but before geese have re-grown their flight feathers and begun their fall migration. Results from this survey shall be completed and delivered to USGS by the end of 2026.

Technical Requirements

Phase 1: Aerial Survey

The survey will be flown in a Piper PA-18 "Super Cub" aircraft at 75–150 m agl and approximately 100–120 km/h. Historically, the survey covered 100% of the estimated extent of the area used for brood rearing by Brant and Snow Geese on the CRD, but starting in 2021, coverage was reduced to 50% due to the increased number and southward range expansion of Snow Geese in the delta (Parrett et al. 2024). During 2021–2023, the survey plane started at the north end of the CRD and surveyed a series of 400-m-wide east-west oriented transects spaced 800 m apart, proceeding southward until no more geese were observed (Figure 1). In 2026, the contractor will follow these methods, but with a modification to get a more accurate count of Brant. The species occurs in relatively few groups and are generally clustered in consistently used wetlands on the north end of the study area and are thus subject to non-representative sampling depending on transect placement. In 2026, contractors will look for all Brant groups between transects, resulting in 100% area coverage for Brant and 50% coverage for Snow Geese.

Phase 2: Reporting

The contractor will provide USGS with a written report detailing methods and results, including timing and geographic extent of the survey, and a map depicting the area surveyed and numbers and locations of adult and young geese observed. They will also provide USGS with a GIS layer of goose group locations, and the set of photographs used to enumerate geese.

Criteria for acceptance: USGS personnel will review reporting information including GIS layers to verify that the task was performed according to specifications.

Deliverable Date

Aerial Survey Late July 2026

Draft Report, geographic database and photographs

15 December 2026

Final Report 31 December 2026 (or 2 weeks after receipt of comments

Supporting Information

Place of Performance: Deadhorse, Alaska (surveys) and Fairbanks, Alaska (photo interpretation and report preparation).

Period of Performance: July 15, 2026, to January 15, 2027 (185 days)

Special Considerations: The survey requires expertise in aerial wildlife survey techniques, as well as extensive experience flying in remote, roadless areas of northern Alaska.

I. GENERAL INFORMATION