2024 Oregon and Washington double-crested cormorant (Nannopterum auritum) colony surveys – aerial photos and count data

Aerial surveys were undertaken to monitor selected double-crested cormorant (DCCO; Nannopterum auritum) colonies in Oregon to fulfill monitoring requirements associated with the United States Fish and Wildlife Service (USFWS) final environmental impact statement: Management of Conflicts Associated with Double-crested Cormorants (USFWS 2020). Survey methods follow guidelines established by the Pacific Flyway Council monitoring strategy: A Monitoring Strategy for the Western Population of Double-crested Cormorants within the Pacific Flyway (PFC 2013). This dataset presents high resolution aerial imagery and corresponding nest counts from areial surveys of double-crested cormorant (DCCO; Nannopterum auritum) colonies in Oregon and Washington. Survey results are intended for use by USFWS and Pacific Flyway Council members, including ODFW and other state and federal agencies, to determine population size and evaluate long-term trends in abundance of DCCO within the Pacific Flyway. Addit..., We conducted aerial surveys at focal double-crested cormorant (DCCO; Nannopterum auritum) colony sites in Oregon and Washington during May and June of 2024. Colony sites were photographed if cormorants were present, or if there were any signs of nesting activity (i.e., nest structures). We also opportunistically surveyed and photographed four supplemental cormorant colony sites along our survey route. Flight timing was based on a best estimate of peak nesting activity from monitoring conducted in previous years and from available published literature. We surveyed and photographed each colony from a fixed-wing aircraft (Cessna 180 Skywagon) at altitudes between 700 and 1,500 feet above ground level. The pilot circled above each target colony, and we used a mirrorless digital camera (Canon R5) with an image-stabilized lens (Canon 100 – 500mm; f/4.5-7.1) to photograph the colonies. Photographs were taken from the front right window of the aircraft, which was opened at survey speeds to redu..., , # 2024 Oregon and Washington double-crested cormorant (Nannopterum auritum) colony surveys Aerial photos and count data

[https://doi.org/10.5061/dryad.jsxksn0mn](https://doi.org/10.5061/dryad.jsxksn0mn)

## Description of the data and file structure

This README file describes the data package for the 2024 Oregon and Washington double-crested cormorant (*Nannopterum auritum*) colony aerial surveys.

Description:

This dataset consists of high-resolution aerial images and corresponding nest counts of double-crested cormorant (DCCO; *Nannopterum auritum*) colonies surveyed in Oregon during 2024. Additional photos of Washington colonies are also provided.

Aerial surveys were undertaken to monitor selected double-crested cormorant colonies in Oregon to fulfill monitoring requirements associated with the United States Fish and Wildlife Service (USFWS) final environmental impact statement, Management of Conflicts Associated with Double-crested Cormorants (USFWS 2020).

USFWS (U.S. Fish and...,