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March 2010

Organization(s): ProNatura Noreste, México; Universidad Autónoma de Nuevo León (UANL)

Project Name and Location: Long-billed Curlew (Numenius americanus) Management in Two Wintering Habitats in the Chihuahuan Desert, Mexico -- Mexico.

Goals

• Conduct winter censuses in two grassland areas to determine the size of long-billed curlew populations.

• Capture individuals for analysis via molecular markers, determination of the subspecies that overwinter in both regions, and the sex of the individuals.

• Determine winter habitat use (mapping critical elements such as night roost sites, watering places, and foraging areas) and local and migratory movements of the species using satellite tracking technology.

• Study the species' winter diet by analyzing regurgitated pellets.

• Capture and band individuals using standard international protocols to evaluate winter site fidelity.

• Set up ponds in both sites as sources of water for the long-billed curlew and establish ranching plans that will help restore the grasslands.

Methods for Monitoring and Evaluation

• Winter census:
  • Samples were taken during the winter periods: October 2007 - March 2008, and October 2008 - March 2009.
  • Monthly field trips were made of 10-12 days each for a total of 24 field days/trips.
  • 40 transects were selected at random, one mile (two kilometers) each, with a buffer area of 350 meters on each side, giving a sampling area of 360 acres (140 hectares) in each zone. The transects were censused according to the methodology described by Ralph (1996) as well as by the distance method (version 5.0) to obtain a real bird density per hectare.
  • The data taken were: date, start time, distance along the line and distance perpendicular to where the bird was found, orientation, activity, and end time.

  Sex and subspecies determination:

  • Individuals were captured only in Nuevo Leon; it was not possible in Janos. Blood samples were obtained for sexing at the molecular level and DNA was extracted from the feathers to determine the subspecies present.
  • Genomic DNA was extracted using the “DNAeasy Tissue Kit” following the industry protocol (Oiagen, Valencia, California, USA).
  • Estimation of gender rates: Molecular sexing was based on an amplification of an intron of the CHD gene using Polymerase Chain Reaction (PCR). DNA was extracted from blood samples. Using the PCR technique and specific primers, conserved regions (exons) and sequences of non-conserved regions (introns) of the CHD gene (Chromodomainhelicase-DNA-binding protein) were amplified, present in both sex chromosomes in order to differentiate females from males. The PCR outcomes were observed in 3% agarose gels. To determine the sex of a bird, the fragment length must be from 400 to 450 base pairs for females (CHDW1) and from 600 to 650 base pairs for males (CHDZ1).
  • Determination of subspecies: To determine whether there was a distinction between parvus and americanus, morphometric and genetic analyses were done using the mitochondrial marker Cytochrome Oxidase I. It was not possible, however, to amplify sequences of COI nor compare them to samples from Canada and the United States. We were able to obtain sequences of ND2 and Cytochrome b genes.

  Satellite tracking and banding:

  • 10 individuals were captured from which five were selected to receive satellite transmitters (two 500-hour battery-powered transmitters and three solar transmitters). Their movements were monitored via a signal with the ARGOS company.
  • Colored bands were placed on all of the birds captured for identification at a distance; the color combinations were determined with a team of researchers from the University of Nevada.

  Winter diet:

  • Pellets were collected at previously identified cattle ponds in both areas where the birds drink water and rest after feeding.
  • The samples were stored in plastic 40-ml jars that were labeled by locality, date, and hour.
  • The pellets were weighed, measured, and analyzed in the laboratory, sorting the prey and food items found for their later identification based on identification guides and taxonomic keys.
  • Insects and seeds were collected in both areas as reference material.
  • Carried out Chi-square (X²) and “T” testing to determine whether there were significant differences in size, weight, and contents in both locations.

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