Methods for measuring populations of small, diurnal forest birds.

Manuwal, David A.; Carey, Andrew B.

doi:10.2737/pnw-gtr-278

Cited by 24 publications

(19 citation statements)

References 11 publications

(21 reference statements)

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“…Ralph et al (1993) and Manuwal and Carey (1991) recommend that bird counts should be completed within 5 hrs after sunrise. But Verner and Ritter (1986) found no hourly differences in species abundance measured 4 to 5 hrs after sunrise.…”

Section: Discussion _____________________mentioning

confidence: 99%

“…Diurnal variation in detectability of birds is widely acknowledged (Robbins 1981, Skirvin 1981. Detections of birds usually depend on certain attributes of singing and calling (Manuwal and Carey 1991) and bird calls or songs often vary regionally (Carey et al 1990). Training observers to recognize songs and calls of local birds is important (Verner and Milne 1989).…”

Section: Discussion _____________________mentioning

confidence: 99%

“…In ponderosa pine, upland quaking aspen, and dry meadow vegetation types, sites were 150-200 m apart and 150 m from the edge of the vegetation type or structural stage (Manuwal andCarey 1991, Robbins et al 1989). In drainage quaking aspen and wet meadows, sites were located >150 m apart, in the center of the drainage; these vegetation types are too narrow to locate sites 150 m from an edge.…”

Section: Methods _______________________ Sampling Designmentioning

confidence: 99%

“…We recorded the time the count began, whether birds observed were within the vegetation type or structural stage being sampled, and the activity of bird. We discontinued bird counts during periods of moderate to heavy rain, when wind velocities exceeded 10 km/hr, or when temperatures were less than 7°C or greater than 24°C (Manuwal and Carey 1991).…”

Section: Bird Countsmentioning

confidence: 99%

“…Therefore, if the frequency that birds sing during the day varies, estimates of bird abundance may be biased if data are collected during periods of low singing frequency (Palmeirim andRabaca 1994, Robbins 1981). Current recommendations are that birds should be counted within 4-5 hrs after sunrise (Ralph et al 1993, Manuwal andCarey 1991). However, these recommendations were made based on data from different regions and vegetation types than occur in the Black Hills.…”

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confidence: 99%

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Optimum timeframes for detecting songbird vocalizations in the Black Hills

Mills¹,

Rumble²,

Flake³

2000

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Birds are indicators of vegetation structure and ecological conditions. The singing activity of birds declines during late-morning periods, which can affect estimates of abundance and conclusions regarding vegetative conditions indexed by birds. Therefore, it is important to quantify periods of bird activity so biologists can plan studies. We determined hourly detections from singing males of 22 nongame bird species in ponderosa pine, quaking aspen, and grassland vegetation types in the Black Hills of South Dakota. Detections of 12 of 22 species differed among 1-hr intervals after sunrise. Detections of yellowrumped warblers, Townsend's solitaires, red-breasted nuthatches, western tanagers, and American robins decreased on count-episodes more than 4 hrs after sunrise. Detections of dusky flycatchers declined on count-episodes more than 3 hrs after sunrise and detections of black-capped chickadees were greatest during the first hour after sunrise and declined afterward. Detections of many other species from songs or calls decreased on count-episodes more than 5 hrs after sunrise. We recommend that bird counts in the Black Hills be completed within 4 hrs after sunrise so estimates of bird abundance are not affected by reduced singing among males.

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Section: Discussion _____________________mentioning

confidence: 99%

Section: Discussion _____________________mentioning

confidence: 99%

Section: Methods _______________________ Sampling Designmentioning

confidence: 99%

Section: Bird Countsmentioning

confidence: 99%

mentioning

confidence: 99%

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Optimum timeframes for detecting songbird vocalizations in the Black Hills

Mills¹,

Rumble²,

Flake³

2000

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A Bird Community Index of Biotic Integrity for the Mid-Atlantic Highlands

O’Connell

Jackson

Brooks

1998

Monitoring Ecological Condition at Regional Scales

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Abstract. We report on the development and preliminary application of a songbird community-based index of biotic integrity. The bird community index (BCI) sorts bird species found at sample sites into a series of values representing the proportional species richness of 20 behavioral and physiological response guilds. Relative proportions of specialist and generalist guilds are used to assign a composite score to each site. Scores from multiple sites indicate the overall biotic integrity of the study area. The BCI is intended to function as a landscape-scale indicator of biotic integrity, integrating conditions across large sample sites containing diverse ecological resources and intensities of human use. We developed the BCI with data from a 1994 pilot study in central Pennsylvania, then applied our preliminary index in 1995 and 1996 to independent samples of sites across the Mid-Atlantic Highlands Assessment area (MAHA). The 1995 and 1996 sample sites were selected using the probability-based sampling design of the Environmental Monitoring and Assessment Program (EMAP), and therefore represent the total land area in MAHA. Our preliminary assessment indicates that MAHA exhibits six categories of biotic integrity, and that more than 40% of the land area supports the two highest biotic integrity categories. Pending BCI refinement and incorporation oflandscape and vegetation explanatory variables, the BCI will be included in a suite of indicators designed to provide an assessment of overall ecological condition in MAHA.

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