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Geology topics

M.A. Howe

Publications and source records attributed to M.A. Howe.

At least 19 recordsLinked to original sources
USGS2005

Enhancing the scientific value of the Christmas Bird Count

T he C hristmas B ird C ount (CBC), conducted by the National Audubon Society (NAS) since 1900, constitutes the longest-running and geographically most widespread survey of bird life in the Western Hemisphere. Starting with 25 count locations in its first year, the program has grown continuously ever since, with 20–30 locations currently being added annually. Each CBC consists of a tally of all birds detected within a circle 24.1 km (15 miles) in diameter, on a single day within a few weeks around Christmas (current allowable dates are 14 December through 5 January). More than 50,000 observers now take part each year, in close to 2,000 count circles spread across the U.S. and its territories, southern Canada, and, increasingly, Latin America.

The Auk↗
USGS1991

Federal research on the conservation of migratory nongame birds in the United States

In the United States, the term 'nongame birds' applies to all bird species that are neither hunted nor legalIy endangered or threatened. Although ultimate responsibility for protection of migratory nongame birds lies with the federal government, research and management efforts by the key federal landholding agencies have historically emphasized species of economic importance, game birds and endangered species. In response to various legislative actions between the late 1960s and early 1980s, however, there has been a gradual escalation of research directed towards conservation of migratory nongame birds in these agencies. These studies have focused on two broad objectives (a) development of population sampling and census methods, and (b) identifying habitat requirements of species and species groups and the impacts of habitat changes on populations. The bulk of this research has been conducted by the U.S. Fish and Wildlife Service and the U.S. Forest Service. In this paper, the missions and research structures of these agencies are described briefly, and selected research highlights are discussed at length. Specific examples are development of the Breeding Bird Survey and teasing apart the relative contributions of forest fragmentation on breeding and wintering grounds to declines in populations of Neotropical migrants. Nongame bird research activities in other agencies are also summarized. The cumulative research conducted to date is evaluated in the context of developing a national management strategy to meet future migratory nongame bird conservation needs. Important shortcomings in present federal programmes continue to be insufficient folIow-through from research results to direct management action and lack of coordination among agencies with a vested interest in nongame bird conservation. Pending legislation and recent maturation of a comprehensive migratory nongame bird policy in the Fish and Wildlife Service are indications that significant improvements in these areas can be expected.

Book chapter↗
USGS1989

Population trends of North American shorebirds based on the International Shorebird Survey

Shorebirds Charadrii are prime candidates for population decline because of their dependence on wetlands that are being lost at a rapid pace. Thirty-six of the 49 species of shorebirds that breed in North America spend most of the year in Latin America. Because populations of most species breed and winter at remote sites, it may be most feasible to monitor their numbers at migration stopovers. In this study, we used statistical trend analysis methods, developed for the North America Breeding Bird Survey, to analyze data on shorebird populations during southbound migration in the United States. Survey data were collected by volunteers in the International Shorebird Survey (ISS). The analyses indicate that whimbrels Numenius phaeopus , short-billed dowitchers Limnodromus griseus , and sanderlings Calidris alba have undergone statistically significant declines. Methodological concerns over both the ISS and the trend analysis procedures are discussed in detail and biological interpretations of the results are suggested.

Biological Conservation↗
USGS1989

Migration of radio-marked whooping cranes from the Aransas-Wood Buffalo population: Patterns of habitat use, behavior, and survival

Use of migration stop-overs by radio-tracked whooping cranes (Grus americana) was studied in fall 1981-83 and spring 1983-84. Information on habitat use, time-activity budgets, and hazards encountered is presented for a sample of 27 individuals, including 9 radio-marked birds. Survival rate is calculated for radio-marked birds and compared with estimates for birds not radio-marked. Distribution patterns of birds for which complete stopover information is available are contrasted with distributions derived from opportunistic observations.

Fish and Wildlife Technical Report↗
USGS1988

Length of stay and fat content of migrant semipalmated sandpipers in eastern Maine

Semipalmated Sandpipers (Calidris pusilla) stop at coastal staging areas in the Canadian maritime provinces and northeastern United States to replenish fat reserves before initiating a nonstop transoceanic flight of at least 3,200 km to wintering areas in South America. The relationship between estimated fat content at capture and length of stay (days between marking and last observation) of Semipalmated Sandpipers at one of these staging areas in eastern Maine was studied during 1980-1982. Total body mass and wing chord length were used to estimate fat content. When data were analyzed by week of initial capture, mean length of stay of both adults and juveniles decreased with increasing fat content. This supports the assumption that resumption of migration is affected by fat content at staging areas for long-distance nonstop flights. However, fat content at capture was a poor predictor of length of stay, which suggests that other factors are more important in determining length of stay.

Condor↗