Long-billed Curlews and Working Lands

By Jay Carlisle and Stephanie Coates, Intermountain Bird Observatory, Boise State University

Long-billed Curlews are not an endangered species but, like all migratory, non-game birds, they are protected by the Migratory Bird Treaty Act. Most western states list curlew as a Species of Greatest Conservation Need, including Idaho’s State Wildlife Action Plan. Reasons for concern include population declines in some portions of the range, altered habitats, and the fact that many grasslands-dependent birds are declining faster than birds in other habitats. The Intermountain Bird Observatory is leading research designed to reveal more about Long-billed Curlew nesting habits and migration to better understand what works well for curlews and how to sustain those habitats while aiming to reverse population declines where they’re occurring.

Long-billed Curlew adult with a curious calf, southwestern Idaho.

Curlew research has been ongoing at the Intermountain Bird Observatory since 2009. For the first four years, our effort was focused on assessing status and reproductive success of a steeply declining population nesting in southwestern Idaho. We soon realized that we needed to expand our scope to other breeding areas and the rest of the annual cycle, since curlews spend eight to nine months (or more) away from breeding areas. Thus, we started to add study areas as well as a new technique – the use of satellite telemetry to track movements of adult Long-billed Curlews. Since 2013, we have worked with many partners to examine population size and reproductive success of Long-billed Curlews in numerous breeding areas of the Intermountain West (i.e., Idaho, Montana, and Wyoming). Amazingly, adults travel from these breeding grounds to wintering areas in California and Mexico.

Early findings of this collaborative research reveal the importance of “working lands” to curlews throughout the year. Among the wide range of habitats they use, Long-billed Curlews rely on many types of working lands both for breeding and in the non-breeding season. Our study results match prior findings in other states that demonstrate how important these habitats are for curlews. In the breeding season curlews will nest in dry grasslands or rangelands, wetter meadows and pastures, agricultural fields including alfalfa, wheat, and even corn (before it gets too tall), and pockets of grassland in sagebrush-dominated areas (see Images 1 and 2). 

Curlew adult incubating a nest with a cow pie nearby, southwestern Idaho.

During the rest of the year, Long-billed Curlews that breed in the Intermountain West migrate to California and Mexico. The habitats they use range from intertidal mudflats (Image 3) to agricultural lands and grasslands in the interior (Image 4). Our hope is that in the near future we’ll be able to build on collaborations with partners in these wintering areas to better understand habitat use patterns and behavior of curlews in different non-breeding habitats. Ultimately, we hope to use all of the information gained to suggest management recommendations for curlews throughout the year, both in agricultural and “natural” habitats.

Long-billed Curlews are unique and fascinating birds that breed in many agricultural and rangeland habitats in the Intermountain West. Our results to date show working lands are critically important to curlews throughout their annual cycle. Maintaining agricultural and rangeland habitats that work well for curlews will be an important element of Long-billed Curlew conservation into the future.