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Stephen DeStefano

Publications and source records attributed to Stephen DeStefano.

39 records · Page 3Linked to original sources
USGS2001

Distribution and abundance of the Yuma clapper rail ( Rallus longirostris yumanensis ) in the Colorado River delta, México

We estimated the abundance of Yuma clapper rails in the Ciénega de Santa Clara and determined the distribution of the subspecies in the Colorado River delta region in México. The maximum estimate of abundance was 6629 individuals (95% C.I. 4859–8399), assuming a response rate by rails to taped calls of 60%. Rails were widely distributed in the delta, occupying almost all marshlands dominated by cattail. As this is an endangered subspecies shared by México and the U.S., the conservation of the delta ecosystem should be the interest of both countries, especially when water management decisions upstream in the U.S. have an impact over natural areas downstream in México.

Journal of Arid Environments↗
USGS2001

Size and mass of grit in gizzards of sandhill cranes, tundra swans, and mute swans

Because it has been suggested that waterbirds may ingest lost or discarded lead fishing weights as grit, we examined grit in the gizzards of Sandhill Cranes ( Grus canadensis ), Tundra Swans ( Cygnus columbianus ), and Mute Swans ( Cygnus olor ), three species where individuals have been poisoned by the ingestion of lead fishing weights. The greatest proportion (by mass) of grit in gizzards of Sandhill Cranes consisted of particles with a minimum dimension of 2.36-4.75 mm. Grit particles in swans were much smaller, with the most prevalent (by mass) being 0.6-1.18 mm. The greatest dimension of the largest grit particle found in cranes and swans was 17.4 mm and 14.0 mm, respectively. The U.S. Environmental Protection Agency has proposed a ban on lead fishing weights of ≤25.4 mm in any dimension. Based on the size of grit particles that we found in gizzards of Sandhill Cranes, Mute Swans, and Tundra Swans, we believe it is unlikely that individuals of those species would ingest, as grit, lead fishing weights larger than 25.4 mm in any dimension.

Arizona, Maryland, Nebraska, New Mexico, Utah↗