Secretive Marsh Birds – Borderlands Avian Data Center

Binational Marsh Bird Network

Background information

Marsh birds include species from the Rallidae and Ardeidae families that strongly depend upon the emergent vegetation and mangroves of freshwater, brackish, and coastal marshes. These birds are very secretive, seldom seen, and are not monitored well with standard bird count procedures. Populations of marsh birds have declined in North America over the last decades. The main cause has been the drastic degradation of wetlands that has occurred on a continental scale, which has been more severe in Western North America and throughout the Sonoran and Mojave deserts.

The lack of reliable data and information about population trends was a cause for concern. In 1999, to better understand the population status of secretive marsh birds, the first standardized survey protocol was developed based on suggestions during a marsh bird workshop at Patuxent Wildlife Research Center (Ribic et al. 1999). That original effort was revised and improved based on a team of experts led by Dr. Courtney Conway to develop the Standardized North American Marsh Bird Monitoring Protocol (Conway 2011). The protocol allows for consistent data collection across North America using a survey method that incorporates a 5-minute passive listening period, followed by a series of 1-minute segments of broadcast calls/listening to increase detection probability of focal marsh bird species. Since that time, the protocol has been adopted by numerous organizations including the U.S. Fish and Wildlife Service National Wildlife Refuge System, Bureau of Reclamation, Bureau of Land Management, California Department of Fish and Wildlife, Arizona Game and Fish Department, and Nevada Department of Wildlife, as well as translated into Spanish for use in Mexico.

Need for range-wide data

Despite the known conservation concern for these species, their status is not well understood. Their reserved nature and nesting habits complicate their observation, thus records for these species are rare. However, the loss and degradation of wetlands in the region and the available data on a few wetlands suggest that populations of marsh birds might be in reduced numbers and declining.

The current threats of drought and ongoing habitat degradation, coupled with information gaps prompted immediate actions towards the conservation of marsh birds in northwestern Mexico. This Binational Network emerged from a regional concern to determine the status and conservation strategies for marsh birds along priority coastal wetlands of the Baja California Peninsula, Sonora, Sinaloa and Nayarit, as well as freshwater wetlands of the Lower Colorado River watershed. Focal marsh bird species include Black Rail (Laterallus jamaicensis), Sora (Porzana carolina), Least Bittern (Ixobrychus exilis), Virginia Rail (Rallus limicola), Ridgway’s Rail (Rallus obsoletus), and American Bittern (Botaurus lentiginosus).

In terms of their protection status, the western subspecies of Black Rail (L.j. coturniculus) is listed as Endangered in Mexico and is being considered for listing in the U.S. The Light-footed Ridgway’s Rail (R.o. levipes), which inhabits coastal marshes of southern California and northern Baja California, is listed as Endangered by both countries. The subspecies of the Lower Colorado River and delta, the Yuma Ridgway’s Rail (R.o. yumanensis), is listed as Endangered in the U.S and is a priority conservation species for CONANP in Mexico. The subspecies from the southern California Coast and the north Pacific coast of Baja California, Light-footed Ridgway’s Rail (R.o. levipes), is listed as Endangered in both the United States and Mexico. Virginia Rails and American Bitterns are listed as Threatened in Mexico, and Least Bitterns are listed as a species under special protection.

Mission

The mission of the Binational Marsh Bird Network is to advance the conservation of these sensitive species by implementing standardized and collaborative monitoring, research and conservation efforts at priority sites in the region.

Goals and Objectives

Our overarching goal is to generate information to guide conservation actions and support adaptive management strategies for secretive marsh birds in northwestern Mexico and the southwestern United States. We have identified four specific goals for the Network which guide activities over the next five years:

Increase capacity in northwestern Mexico, the southwestern United States, and binationally to monitor and protect marsh birds by organizing meetings, workshops, and field trainings for biologists and volunteers.
Collect data needed to support conservation actions by implementing the Standardized Protocols for Monitoring Marsh Birds in North America in priority sites to generate information on the distribution, relative abundance, status, and population trends of these birds
Implement strategic research projects, including studies on habitat use, migration ecology, productivity, survival rates, and taxonomy.
Support the integration, archiving, and analysis of data to facilitate uses at the local, regional, and continental levels, through training and promotion of the Borderlands Avian Data Center.
Implement conservation actions for marsh birds and their habitats throughout their ranges, including updating the protection status of sensitive species and subspecies, identifying priority sites and their threats, and implementing site conservation mechanisms.

Membership

Participation in the Network is open to anyone from academic, non-profit, private, and public organizations that is interested in the activities and in advancing the goals of the group. Current participating organizations include CIAD, CICESE, CONANP, Pro Esteros, Pronatura Noroeste, the Sonoran Joint Venture, the Bureau of Reclamation, and the U.S. Fish and Wildlife Service (Arizona Ecological Services and National Wildlife Refuge System). If you are interested in joining the Network, please contact Osvel Hinojosa, who represents Pronatura Noroeste and The Cornell Lab of Ornithology.

Marsh Bird Surveys

The National Marsh Bird Monitoring Program was developed to help the National Wildlife Refuge System implement the standardized survey across refuges. The National Wildlife Refuge System Protocol Framework for the Inventory and Monitoring of Secretive Marsh Birds (Conway and Seamans 2016) is now in widespread use across various land management entities in Mexico and the U.S., and data are entered into the Avian Knowledge Network through the Borderlands Avian Data Center.

To learn more about the program or to sign up for future marsh bird trainings in the U.S., please contact Rebecca Chester, USFWS Zone Biologist for the Lower Colorado River Valley Refuges. To learn more about the program or training opportunities in Mexico, contact Osvel Hinojosa or Steffany Villagómez.