Initial deadline for comments: 31 January 2012.
Sinaloa Martin Progne sinaloae breeds in pine-oak forest and semi-open habitats at nine sites on the western slope of the Sierra Madre Occidental in Mexico. It still appears to occupy its traditional breeding range from Sonora to Michoacán, with recent records from Guerrero (Lethaby and King 2010). Breeding has been recorded historically in Sonora, Chihuahua, Sinaloa, Nayarit, Jalisco and Michoacán; of these, it is still known to breed in Sinaloa and Jalisco (Lethaby and King 2010). It has been recorded on migration in Mexico and casually in Guatemala and Belize, but its wintering range, conservation status and population trends are unknown. For these reasons the species has been assigned to the category Data Deficient.
However, a comprehensive review of records by Lethaby and King (2010) suggests that there may be sufficient information available for an assessment of the species’s threat status against the IUCN criteria; indeed, the authors recommend that the species be listed as Endangered under criterion C2a(ii), with a declining population and fewer than 2,500 mature individuals remaining.
A number of rough indices can be used to infer a decline in population: as Lethaby and King (2010) point out, historical records typically comprised multiple specimens from a given location and include statements such as ‘common’, ‘quite a colony’, ‘up to 15’, and ‘up to 30’ that clearly indicate the existence of sizeable colonies, whereas recent records are usually of migrants in the lowlands, with the only definite breeding record being a colony of just 2–6 birds (Lethaby and King 2010). Lethaby and King (2010) consider it unlikely that the population numbers more than a few thousand, and based on current knowledge, a population estimate of fewer than 10,000 mature individuals may be realistic, potentially qualifying the species as Vulnerable under criterion C2a(ii).
Without sufficient information on the species’s sub-population structure, however, the species will most likely qualify as Near Threatened, based on the suppositions above. Information is thus requested on whether 90% or more of all mature individuals probably form one sub-population or alternatively the likely maximum number of mature individuals in the largest sub-population. For the purposes of Red List assessments, sub-populations are defined as geographically or otherwise distinct groups between which there is little or no demographic or genetic exchange, i.e. typically one successful migrant per year or less.
We would also welcome further estimates of the current population size, opinion on the evidence for a population decline and any further sightings.
Lethaby, N. A. and King, J. R. (2010) The current status of Sinaloa Martin Progne sinaloae. Cotinga 32: 90-95.
The following document was sent by Pronatura on 16 February 2012: Progne Sinaloae Pronatura Feb12