Geology topics

Harold F. Greeney

Publications and source records attributed to Harold F. Greeney.

4 recordsLinked to original sources

USGS2024

Utilizing artificial nesting platforms as a management tool: Enhancing breeding productivity of Western Flycatchers (Empidonax difficilis occidentalis) in southwestern Colorado and southern Arizona, USA

Artificial nesting substrates have been added around the world for many cavity-nesting bird species, but this has not been undertaken as extensively for crevice-nesting birds. The Western Cordilleran Flycatcher ( Empidonax difficilis occidentalis ) is a migratory, crevice-nesting flycatcher that is nest-site limited, breeding in higher elevation riparian habitats throughout intermountain western North America. We tested the effectiveness of multiple artificial nesting platform types that this flycatcher would accept for nesting, and then utilizing the successful design established an experimental array of platforms in southwestern Colorado and southern Arizona. From 2008 to 2022 we documented Cordilleran Flycatcher breeding and the influence of nesting platforms on productivity of young and adult numbers. Breeding behaviors did not differ significantly between natural nest sites and platform nests, except that the nestling period was an average of 16.73 (+/- 0.98) days on platforms as compared to 15.92 (+/- 0.71) on human structures and 15.67 (+/- 0.48) days in natural locations. Platform nests had lower predation rates and greater rates of successful fledging when compared to natural locations. At both study locations platform nests doubled the number of young fledged each year. In Colorado, where Western Cordilleran Flycatchers were initially absent from areas, adult numbers increased following introduction of platforms, but in Arizona adult flycatcher numbers were not affected. Our findings demonstrate that the addition of artificial nesting platforms can enhance productivity and numbers of Western Cordilleran Flycatchers, and we hope that our findings will prove useful for the conservation of other crevice-nesting bird species.

Arizona, Colorado↗

USGS2023

The importance of Sky Islands in the annual cycle of the Western (Cordilleran) Flycatcher Empidonax occidentalis

For more than a century and a half the Madrean sky islands, a group of 55 mountain ranges that occur from the middle of Arizona to the southern end of Sonora Mexico and rise from the desert floor to 3,000-10,000 feet elevation, have been a Mecca for ornithologists and natural historians. The ornithological literature of the late 19th early 20th centuries is filled with the wonderfully detailed and colorful accounts of expeditions and discoveries by Charles Bendire, Elliott Coues, William Brewster, William Earl Dodge Scott, Harry S. Swarth, and Herbert Brandt, to name but a few. The Huachuca, Santa Rita, and Chiricahua Sky Islands in particular, received a great deal of attention, being renowned for producing rare Mexican strays --- Recent sightings of The Red Warbler and Brown Flycatcher at Rose Canyon on Mt Lemmon attest to the continued northward movement of species that are usually only seen in Mexico. Throughout the 20th century, ornithologists such as Russell P. Balda, Steven M. Russell, James T. Marshall Jr., and J. David Ligon produced a wealth of natural history information, while long-term studies, such as that of Jerry and Esther Brown on Mexican Jays in the Chiricahuas, made substantial and lasting contributions to our knowledge and understanding of birds.

Newsletter↗

USGS2019

Observations on the range and nesting biology of the Mexican endemic rufous-capped brush-finch (Atlapetes Pileatus Pileatus)

The Rufous-capped Brush-finch ( Atlapetes pileatus ) is a species endemic to Mexico, whose breeding biology has received little attention. We studied two nests of the nominate subspecies from the mountains of southern Sonora. Nests were untidy, broad, open cups, placed in low, thick vegetation. Clutch size at one nest consisted of three immaculate white eggs. The second nest contained two Brush-finch nestlings and one cowbird ( Molothrus sp.) nestling. Both parents brought food to the nestlings, but delivered significantly more food to the cowbird nestling. Most of our observations of nest architecture, egg coloration, and adult behaviors are consistent with previous descriptions for Rufous-capped Brush-finch and other members of the genus Atlapetes . This is the first report of cowbird brood-parasitism on the Rufous-capped Brush-finch, as well as the first confirmed record of breeding by this species in Sonora.

Ornitología Neotropical↗

USGS2017

Importance of the 2014 Colorado River Delta pulse flow for migratory songbirds: Insights from foraging behavior

The Lower Colorado River provides critical riparian areas in an otherwise arid region and is an important stopover site for migrating landbirds. In order to reverse ongoing habitat degradation due to drought and human-altered hydrology, a pulse flow was released from Morelos Dam in spring of 2014, which brought surface flow to dry stretches of the Colorado River in Mexico. To assess the potential effects of habitat modification resulting from the pulse flow, we used foraging behavior of spring migrants from past and current studies to assess the relative importance of different riparian habitats. We observed foraging birds in 2000 and 2014 at five riparian sites along the Lower Colorado River in Mexico to quantify prey attack rates, prey attack maneuvers, vegetation use patterns, and degree of preference for fully leafed-out or flowering plants. Prey attack rate was highest in mesquite (Prosopis spp.) in 2000 and in willow (Salix gooddingii) in 2014; correspondingly, migrants predominantly used mesquite in 2000 and willow in 2014 and showed a preference for willows in flower or fruit in 2014. Wilson’s warbler (Cardellina pusilla) used relatively more low-energy foraging maneuvers in willow than in tamarisk (Tamarix spp.) or mesquite. Those patterns in foraging behavior suggest native riparian vegetation, and especially willow, are important resources for spring migrants along the lower Colorado River. Willow is a relatively short-lived tree dependent on spring floods for dispersal and establishment and thus spring migrants are likely to benefit from controlled pulse flows.

Arizona, California↗