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Geology topics

Colleen M. Handel

Publications and source records attributed to Colleen M. Handel.

68 records · Page 4Linked to original sources

Recommendations for the use of mist nets for inventory and monitoring of bird populations

We provide recommendations on the best practices for mist netting for the purposes of monitoring population parameters such as abundance and demography. Studies should be carefully thought out before nets are set up, to ensure that sampling design and estimated sample size will allow study objectives to be met. Station location, number of nets, type of nets, net placement, and schedule of operation should be determined by the goals of the particular project, and we provide guidelines for typical mist-net studies. In the absence of study-specific requirements for novel protocols, commonly used protocols should be used to enable comparison of results among studies. Regardless of the equipment, net layout, or netting schedule selected, it is important for all studies that operations be strictly standardized, and a well-written operation protocol will help in attaining this goal. We provide recommendations for data to be collected on captured birds, and emphasize the need for good training of project personnel

Studies in Avian Biology

Densities of breeding birds and changes in vegetation in an alaskan boreal forest following a massive disturbance by spruce beetles

We examined bird and plant communities among forest stands with different levels of spruce mortality following a large outbreak of spruce beetles (Dendroctonus rufipennis (Kirby)) in the Copper River Basin, Alaska. Spruce beetles avoided stands with black spruce (Picea mariana) and selectively killed larger diameter white spruce (Picea glauca), thereby altering forest structure and increasing the dominance of black spruce in the region. Alders (Alnus sp.) and crowberry (Empetrum nigrum) were more abundant in areas with heavy spruce mortality, possibly a response to the death of overstory spruce. Grasses and herbaceous plants did not proliferate as has been recorded following outbreaks in more coastal Alaskan forests. Two species closely tied to coniferous habitats, the tree-nesting Ruby-crowned Kinglet (Regulus calendula) and the red squirrel (Tamiasciurus hudsonicus), a major nest predator, were less abundant in forest stands with high spruce mortality than in low-mortality stands. Understory-nesting birds as a group were more abundant in forest stands with high levels of spruce mortality, although the response of individual bird species to tree mortality was variable. Birds breeding in stands with high spruce mortality likely benefited reproductively from lower squirrel densities and a greater abundance of shrubs to conceal nests from predators.

Canadian Journal of Zoology

Mate fidelity and breeding site tenacity in a monogamous sandpiper, the black turnstone

We examined the relationship between mate fidelity and breeding site tenacity during a 5-year study of the black turnstone, Arenaria melanocephala, a socially monogamous sandpiper breeding in subarctic Alaska. We tested the predictions of several hypotheses regarding the incidence of divorce and the benefits of fidelity to mate and breeding site. Interannual return rates to the breeding grounds (88% for males, 79% for females) were among the highest yet recorded for any scolopacid sandpiper, and 88% of returning birds nested on their previous year's territory. The annual divorce rate was only 11%, and mate fidelity was significantly linked to fidelity to territory but independent of sex and year. Males arrived in spring significantly earlier than their mates and interannual fidelity was influenced by the relative timing of arrival of pair members. Reunited pairs had significantly higher fledging success than new pairs formed after death or divorce. The incidence of divorce was unrelated to reproductive success the previous year, although birds nested significantly further away after failure than after a successful nesting attempt. Sightings of marked individuals suggested that members of pairs do not winter together, and breeding site tenacity provides a mechanism through which pair members can reunite. We reject the 'incompatibility' hypothesis for divorce in turnstones, and our data contradict predictions of the 'better option' hypothesis. Alternatively, we propose the 'bet-hedging' hypothesis to explain the occurrence of divorce, which transpires when an individual pairs with a new mate to avoid the cost of waiting for a previous mate to return. Such costs can include remaining unmated, if the former mate has died, or experiencing lower reproductive success because of delayed breeding.

Animal Behaviour

Roosting behavior of premigratory Dunlins ( Calidris alpina )

We studied roosting behavior of Dunlins ( Calidris alpina ) during late summer along the coast of the Yukon-Kuskokwim Delta, Alaska, in relation to tidal cycle, time of day, time of season, and occurrence of predators. Within Angyoyaravak Bay, peak populations of 70,000-100,000 Dunlins occur each year. The major diurnal roost sites were adjacent to intertidal feeding areas, provided an unobstructed view of predators, and were close to shallow waters used for bathing. At one site studied intensively, roosting flocks formed at high water consistently during the day but rarely at night. On about 75% of the days, Dunlins also came to the roost at dawn and dusk when the tide was low. The size of the roosting flock, the length of time birds spent at the roost site, and behavior at the roost site were highly variable throughout the season and significantly affected by both tide level and time of day. Roosting behavior changed significantly between early and late August, as Dunlins underwent heavy wing and body molt, and began premigratory fattening. The reaction of Dunlins to potential predators, the formation of roosting flocks in response to light cues, and seasonal changes in social behavior at the roost site suggested that communal roosting behavior may be related not only to the risk of predation but also to behavior during migration.

Alaska

Breeding distribution of the Black Turnstone

Eighty-five percent of the world population of Black Turnstones ( Arenaria melanocephala ) nest on the central Yukon-Kuskokwim Delta, Alaska, 65% concentrated in a narrow band of salt grass, graminoid, and dwarf shrub meadows within two km of the coast. An estimated 61,000 to 99,000 birds (95% CI), with a point estimate of 80,000 birds, breed on the central delta. About 15,000 others nest elsewhere in Alaska. Abundance varies among habitats and with distance from the coast. On the central delta, highest breeding densities occur in coastal salt grass meadows (1.11 ± 0.16 birds · ha-1) and lowest densities occur on dwarf shrub mat tundra (0.04 ± 0.04 birds · ha-1). Breeding densities in mixed graminoid and dwarf shrub meadows decline significantly with distance from the coast, decreasing abruptly from 0.75 ± 0.11 birds · ha-1 within the first two km to 0.09 ± 0.03 birds · ha-1 farther inland. Although salt grass meadows constitute only 5% of the coastal lowlands, they support 25% of the population.

The Wilson Bulletin

Observations on habitat use, breeding chronology and parental care in Bristle-thighed Curlews on the Seward Peninsula, Alaska

Results from an intensive survey in 1989 of one of the two known breeding localities of Bristle-thighed Curlews Numenius tahitiensis are reported. During the pre-nesting period birds confined most of their activity to two vegetation communities: shrub meadow tundra and low shrub/tussock tundra. During nesting more than half the Curlews seen were observed on shrub meadow tundra, whilst during brood rearing, use of low shrub/tussock tundra continued to decline in importance as birds attending young increased their use of sedge wet meadows. Despite extensive searches no nests were located; however, observations of broods indicated that nest initiation began around 25 May and that hatching occurred during the last week of June. Detailed observations are presented on the formation of four brood-groups, some of which held different combinations of unrelated adults or young. The adaptive significance of this unusual wader behaviour is discussed.

Alaska

The importance of subarctic intertidal habitats to shorebirds: A study of the central Yukon-Kuskokwim Delta, Alaska

A 6-year study of shorebird use of intertidal habitats of the Yukon-Kuskokwim Delta revealed this area to be one of the premiere sites for shorebirds throughout the Holarctic and worthy of designation as a Hemispheric Shorebird Reserve in the Western Hemisphere Shorebird Reserve Network. The study area, which covered 10% (300 km 2 ) of the delta's intertidal flats, regularly hosted 17 species of shorebirds between late April and mid-October. The greatest use was during the postbreeding period (late June-October), when Dunlins ( Calidris alpina ), Western Sandpipers ( C. mauri ), and Rock Sandpipers ( C. ptilocnemis ), each with large local nesting populations, accounted for 95% of the shorebirds recorded. Peak counts during autumn approached 300,000 birds. Considering the seasonal occurrence and turnover of populations, we estimate 1-2 million shorebirds use the central delta each year. The delta supports large fractions of the Pacific Rim or world populations of Bar-tailed Godwits ( Limosa lapponica ), Black Turnstones ( Arenaria melanocephala ), Red Knots ( C. canutus ), Western Sandpipers, Dunlins, and Rock Sandpipers. Densities of shorebirds using the central delta's four major bays and connecting coastal areas peaked at 950 shorebirds/km 2 in early September. Hazen Bay frequently hosted more than 1,200 shorebirds/km 2 . Postbreeding shorebirds used intertidal habitats in three distinct patterns according to age class. For most species (n = 7), there was a period when adults appeared first, followed by a brief interval when adults and juveniles mixed, then by a prolonged period when only juveniles remained. In the second pattern (n = 3 species), adults moved onto the intertidal flats first, were later joined by juveniles for a prolonged staging period, then migrated with them. In the third pattern (n = 3 species), only juveniles used the delta's intertidal habitat. Temporal segregation among species and age groups may minimize competition for food and thereby allow the delta to support high diversity and numbers of shorebirds.

Alaska

Factors influencing predation associated with visits to artificial goose nests

Artificial goose nests were used to determine what factors might increase predation after visits to nests of Cackling Canada Geese ( Branta canadensis minima ). We tested whether leaving the nest uncovered, marking the nest location with a flag, or placing the nest on an island or peninsula would increase the rate of predation. Predators destroyed significantly more of the nests with eggs exposed to view (61%) than of the nests with eggs covered with goose down (35%) (P < 0.05). However, the rate of predation was only slightly higher among nests located on peninsulas than on islands and equal proportions of flagged and unflagged nests were destroyed. We also determined that investigators attracted predators to the study area and caused an increase in predation at uncovered nests immediately after the visit. Covering the eggs with down essentially negated the effect of attracting predators when visiting the nest. Among the 46 nests destroyed, 78% were destroyed by birds and 22% by mammals. Results of our study suggested that visibility of exposed eggs rather than nest markers provided important cues to avian predators and that islands probably provided some refuge from mammalian predators. Investigators can take steps to minimize their impact on nesting success and should incorporate a measure of that impact in their studies.

Alaska

Memorial to a Black Turnstone: An examplar of breeding and wintering site fidelity

Most of us who have banded long-distance migrants are aware, through recaptures of individuals, of the high degree of site fidelity exhibited by many bird species. It is not uncommon for a bander to have a marked bird remain in the vicinity of its banding site throughout a season and then to recapture or sight the bird there during the following season, or occasionally for several successive seasons. However, these "special" birds are rarely encountered away from the banding site and, if they are, it is usually because they have died and the band has been reported. Rarely do we get multiple recaptures or resightings of an individual bird that allow us to compare site fidelity at the two ends of its migration route or to determine the timing of movements between these points. Here we describe an instance of a uniquely marked Black Turnstone ( Arenario melanocephola) that was studied on both its breeding and wintering grounds for 5 consecutive years. We believe this represents one of the most detailed accounts of this nature for a North American bird.

North American Bird Bander

Yellow birds stand out in a crowd

Highly visible auxiliary markers, such as neck collars, nasal saddles, patagial tags, and leg streamers, are used regularly and effectively with banding in studying migration and distribution of large birds (e.g. waterfowl, birds of prey, wading birds). Simply stated, a large bird can accommodate a marker that is large enough to be seen readily by an observer but still small enough not to alter behavior or impair flight (see Marion and Shamis 1977 for review). Such is not true with smaller birds, and consequently information on their migration routes and distribution is usually poorer than for larger birds. The use of colored leg bands increases the frequency of detection of small birds that have been banded; however, a large percentage of such marked birds is usually still overlooked. Only by using highly visible techniques, such as plumage dyes and bleaches in conjunction with leg bands, can one obtain significant numbers of sightings of small birds. Here we present information from sightings of large numbers of marked Dunlins ( Calidris alpina ) and Western Sandpipers ( C. mauri ) that dramatically demonstrates this.

North American Bird Bander

An annotated bibliography of literature on Alaska water birds

The demand for information on birds in Alaska has surged within the past few years, primarily because of the need to adequately assess the impacts of a wide range of planned developments. The accompanying increase in studies of avian populations has resulted in a growing need for a comprehensive bibliography of Alaska ornithology. An initial effort by Bartonek and Lensink (1978) provided a list of published and unpublished references on marine birds, but this list was only marginally useful because it lacked adequate indexing and annotation of references cited. Their bibliography, however, plus those of Cade (1953) and Gabrielson and Lincoln (1959), provided the basis and primary reference sources for our work. In the present bibliography we have attempted to compile all substantive references addressing water birds in Alaska because this group of birds appears to be most Vulnerable to repercussions of development, particularly along the coast. However, the works cited make up an estimated 70-80% of all literature on birds in Alaska, and this volume thus provides an initial source of references on terrestrial birds. This bibliography, which contains 1554 citations, is current for most journal sources through 1979 and most of 1980. The content of each paper has been summarized, and we have indexed the citations by subject, species, and geographic location to make the bibliography a more useful reference. Furthermore, the bibliography has been designed to facilitate future inclusion of references that have been omitted or that will be published in the rapidly growing body of literature on Alaska birds.

Alaska