Effects of Aleutian Geese on Humboldt County Pastures

Project Overview

Project Type: Farmer/Rancher
Funds awarded in 2008: $28,540.00
Projected End Date: 12/31/2009
Region: Western
State: California
Principal Investigator:
Alan Bower
University of California Davis


  • Agronomic: grass (misc. perennial), hay
  • Animals: bovine


  • Animal Production: grazing - continuous, pasture fertility, feed/forage
  • Education and Training: extension, on-farm/ranch research
  • Pest Management: field monitoring/scouting


    Aleutian cackling geese (Branta hutchinsii leucopareia) stop in Humboldt County, California, and feed on private pasture lands during their yearly migration. Their expanding population has led to increased conflicts over forage consumption and, ultimately, available forage allocation for beef cattle on ranches in Humboldt County, California. A research project was developed to quantify Aleutian cackling goose forage consumption and effects on pasture production rates on three private beef ranches in Humboldt County. Data collection occurred during late winter 2008 and early spring 2009. Pasture production was estimated under conditions of no grazing, grazing by cattle only, and grazing by cattle and geese. The results of this study show that Aleutian cackling geese are having a statistically significant impact on pasture production.


    Aleutian cackling geese (Branta hutchinsii leucopareia) use private pasture lands in Humboldt County, California, as a staging area on their migration from wintering grounds in California’s Central Valley to breeding grounds of the Aleutian Islands in Alaska. Aleutian cackling geese were listed as an endangered species in 1973 when less than 800 birds were recorded. Successful conservation measures allowed the population to expand, and they were delisted in 2001. The population estimate for 2005 was over 100,000 (USFWS 2008). Almost the entire population spring stages in the northern California coastal region (Bachman 2008).

    Geese have selective feeding behaviors and prefer plants that have low fiber and high protein content (Riddington et al. 1997). This ratio is found more readily in newer plant growth (Langer 1973), which can be stimulated by maintaining forages at a short stubble (leaf) height. Rotational grazing practices are one way to keep short stubble heights. Many local ranchers adopted these practices within recent years for economic and ecological sustainability. This management practice has proved to be highly attractive to Aleutian cackling geese. As the population continues to increase, they exert increased grazing pressure on local private ranch lands. This pressure has created conflicts in forage utilization and the subsequent allocation of available forage to livestock production versus consumption by the geese.

    Project objectives:

    This project was designed to address the economic impacts of Aleutian cackling goose grazing on three local beef ranches by providing an analysis of the forage partitioning between use by geese and that for beef production. Estimates of pasture production were calculated with the use of empirical data collected under 3 conditions: 1) with no grazing by cattle or Aleutian cackling geese, 2) with grazing by cattle only, and 3) with grazing by cattle and Aleutian cackling geese.

    Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.