Professor posing with equipment in a lab

Wood Stork Research

Ramstad Lab


Wood storks (WOST, Mycteria americana) are large, non-migratory wading birds that inhabit wetlands of the southeastern US, the Caribbean, Central America and South America.  They are the only stork that breeds in North America and are listed as Threatened by the US Fish and Wildlife Service (USFWS).

My collaborators and I have sampled WOSTs from the extremes of their range and are developing a powerful panel of SNP markers via 3RAD  and sequence capture techniques.  The questions we plan to address are below.

How many populations are there of WOST?

Four studies have attempted to describe the genetic population structure of WOST, and all found a lack of divergence among nesting colonies. These findings led researchers to suggest that WOST comprise a single, panmictic population worldwide, which in turn has led the USFWS to manage US WOST as a single population.  These studies, however, suffered from limited sampling and low statistical power.

We are undertaking a broad genomics study of WOST to define the proper scale of management, assess the susceptibility of individual colonies to local extinction, and determine appropriate source populations for potential future translocations.

Are WOSTs nest parasites?

Wood storks nest colonially in wetland trees and are thought to be monogamous within annual breeding seasons. The WOST mating system is characterized by high parental investment, high nest density, intense aggression, and competition for nesting resources. These conditions may promote promiscuity (copulation with partners outside of the social pair) and/or intraspecific nest parasitism (where females lay eggs in nests of other females from the same species).

We are using mtDNA and SNP data to assess the prevalence of extra pair matings and nest parasitism among US WOST. To do this, we are genotyping all chicks within the same nest to ask if 1) they share the same mother and 2) are full-siblings.  A total of 312 chicks, from 119 independent nests from 5 US colonies are being genotyped for this analysis.

Can remote camera traps effectively monitor WOST nests?

We are testing a sampling protocol to monitor WOST nests via remote camera traps.  Such a method could be vastly more efficient than traditional visual observation and allow a significant increase in the number of US WOST breeding colonies that are monitored annually. In our 2017 pilot season, we captured over 32 thousand pictures of 28 nests in a single inland WOST colony.

We are refining this method and will use it to assess the proportion of chicks that successfully fledge from a nest (fledging success), the time period between chicks hatching and fledging (fledge time) and the degree to which these are correlated with patterns of parental behavior (frequency of feeding, nest guarding).

Project collaborators

  • Larry Bryan & Dr Stacey Lance, Savannah River Ecology Lab, University of Georgia
  • Drs Natalia Bayona & Travis Glenn, EHS DNA Laboratory, University of Georgia
  • Dr Silvia Nassif del Lama & Fagner Miguel da Silva, Departamento Genética e Evolução, Universidade Federal de São Carlos, BRAZIL
  • Dr Georgina Espinosa, Facultad de Biologia, Universidad de la Habana, CUBA


  • University of South Carolina Aiken

Support in-kind & field work

  • Tim Keyes (GDNR)
  • Chris Depkin
  • Chuck Hayes (USFWS)
  • Kimberly Hayes (USFWS)
  • Chris Thornton (GDNR)
  • Donna Bear (Jacksonville Zoo)
  • Christy Hand (SCDNR)
  • Chip Patterson
  • David Hodges
  • Megan Oberkircher
  • David Scott
  • April DeLaurier
  • Jamie Pommersheim
  • Ewan Hunter
wost chicks
ramstad with wost chick
wost nest