Modeling Regional Source-Sink Dynamic

For Migratory Songbirds in Inform Management Practices on Department of Defense Installations


Maintaining viable populations of migratory songbird species remains a priority management issue for the Department of Defense. Habitat quality often influences population viability; high-quality habitats have more births than deaths (sources) and low-quality habitats have more deaths than births (sinks).

As such, managing migratory bird populations on more than 30 million acres of critical wildlife habitat requires detailed knowledge of patterns of birth and death through time and how land use practices and landscape configuration influence vital rates and population persistence.

In addition, many migratory songbird species spend the majority of their annual cycle in tropical latitudes, which requires managers to understand how the overwinter period influences population dynamics.

Proposed Study

  • The Smithsonian Institution, Institute for Bird Populations, Oregon State University, and the Engineer Research and Development Center (ERDC) of the US Army Corps of Engineers have been funded by the Strategic Environmental Defense Research Program (SERDP) to study population dynamics of wood thrush (Hylocicla mustelina) on Department of Defense installations.
  • From 2011 to 2014, wood thrush breeding population dynamics will be tracked at Crane Naval Surface Warfare Center and Big Oaks National Wildlife Refuge in Indiana and at Fort Knox in Kentucky. map showing study locations
  • This project will test and validate 3 methods for identifying population sources and sinks:
    1. Point counts (patch occupancy modeling),
    2. Constant effort mist-netting (MAPS),
    3. Intensive demographic studies (directly measuring nesting success and survival of color-banded thrushes).
  • In 2011, the wintering locations of wood thrushes breeding on our 3 installations will be determined using geolocators. Tropical study sites will be established for monitoring of these linked populations from 2012 to 2014.
  • These data will be used to determine the local and landscape characteristics that predict source-sink dynamics and to construct models of regional population persistence.

Management Objectives

  • Produce a managers' guide that describes how to identify source-sink habitats.
  • Hold workshops to train DoD biologists in how to assess and manage migratory songbird populations in complex landscapes.
  • Make management recommendations that foster healthy populations of threatened and endangered songbird species while ensuring no net loss of the capability of DoD lands to support the military mission.

SMBC Investigators:

  • Pete Marra
  • Scott Sillett
  • Brandt Ryder


  • Phil Nott and James Saracco, Institute for Bird Populations
  • Matthew Betts, Oregon State University
  • Richard Fischer, US Army Environmental Research and Development
brown spotted bird