Avian field studies commonly employ colored leg bands to follow individual birds without recapturing them. However, this technique is subject to several types of reporting errors. In a laboratory setting under ideal conditions, we marked model birds with colored band combinations to examine resighting rates and errors made by trained and untrained observers. We varied both the time of exposure and the number of birds presented to observers in a series of replicate trials. We found large variation in the number of incorrectly recorded combinations among both trained and untrained observers. The mean error rate for trained observers was 5%, and for untrained observers was 16%. In both groups, error rates significantly increased when observers were exposed to more birds or observation intervals were short. The most common type of error involved switching band combinations on left and right legs. In some cases incorrectly recorded combinations matched actual combinations used on other birds. We also found that resighting probabilities depended on the particular colors used. Because this study was performed under indoor lighting conditions and at a relatively close distance (to mimic conditions under which birds are viewed at nearby feeders), we suggest that the error rates we observed likely represent low estimates and that error rates under field conditions will be higher.

We investigated the effects of varying census duration on line transect estimates of winter bird abundance and species richness in second-growth coastal western hemlock forest fragments in Vancouver, British Columbia. Three treatments of census duration (12 min, 18 min and 24 min) were compared on 200 m-long transects at three study sites over three fortnights in a replicated latin square experimental design. Overall, census duration affected the number of individual birds and bird species detected. The number of individual birds detected increased significantly with census duration from 12 min to 18 min but not from 18 min to 24 min. The number of bird species detected also increased with census duration, although the increase was significant only between 12 min and 24 min. The results suggest that for winter bird counts in coastal western hemlock forest, a census duration of 18 min for a 200 m-long transect is most efficient.

Feather growth bar widths have become a standard index of nutritional condition in ornithological research. Traditional techniques of measuring these bars are difficult and slow because the bars are often hard to see. We present a fast and repeatable method of visualizing and measuring growth bars using a gel documentation system from Alpha-Innotech Corporation. This system takes digital photos of objects in a low light chamber. These photos can then be enhanced and measured on a computer. We show that this system can be used to quickly obtain repeatable measurements of growth bars that are highly correlated with those obtained using traditional methods. The high repeatability and low inter-observer variability of our results also validates more traditional methods of ptilochronology.

We evaluated nasal discs and colored leg bands for Harlequin Ducks (Histrionicus histrionicus) wintering in the Strait of Georgia, British Columbia, by comparing marker visibility and life span, and determining effects of nasal discs on behavior and pairing. Proportions resighted and frequency of sightings were higher for individuals marked with nasal discs than for those marked only with leg bands. Nasal disc loss followed a logistic function that predicted 50% loss by 396 d. Due to wear of leg bands, number of sightings per individual decreased with leg band age following a cubic function. We detected no effects of nasal discs on time spent in various behaviors, timing of pairing, or female pairing success. However, males with nasal discs had lower pairing success, and females with nasal discs were less likely to reunite with previous mates. We speculate that the effect of nasal discs on male pairing success may be due to a male-biased sex ratio and sexual selection on male appearance. Leg band wear should be considered for demographic models because its effects can violate assumptions and bias sighting and survival estimates.

The Galapagos Rail (Laterallus spilonotus) is endemic to the Galapagos Archipelago and little is known of its current status or population trends. In 2000, we surveyed 280 points in the largest population, on Santa Cruz Island, using call broadcast methods identical to those used in a baseline survey of the same area in 1986. The probability of detecting rails at sample points declined from 36% to 27% between surveys. An invasive woody plant, Cinchona succirubra, was not detected in 1986 yet was present at nearly three-fourths of survey points in 2000 and was avoided by rails in 2000. We recommend that future research and monitoring be conducted to determine the importance of Cinchona removal programs for maintaining this largest of populations of the Galapagos Rail.

From March 1999 to August 2000, we used mist-netting, point counts, and radio-tracking to study habitat use, area requirements, and breeding of the Ivory-billed Woodcreeper Xiphorhynchus flavigaster in the tropical deciduous and semi-deciduous forest (arroyo forest) of the Chamela-Cuixmala Biosphere Reserve, western Mexico. The Ivory-billed Woodcreeper was a common, year-round resident. Breeding commenced at the end of the dry season (May) and continued during the rainy season through August. Our observations suggested that only the female builds the nest, incubates, and feeds nestlings. Ivory-billed Woodcreepers commonly foraged alone, but sometimes joined mixed-species flocks that passed through their territories, occasionally following army ant swarms. Home-range size varied from 6–36 ha, although most birds' home range was 15 ha or less. We did not find differences in home range size or mobility between the dry and rainy seasons, and we did not find a correlation between the size of the home range and the extent of semi-deciduous forest it included. We did not find evidence that suggested a greater use of semi-deciduous forest than of dry deciduous forest. We hypothesize that foraging habits and low competition could explain the lack of selection for semi-deciduous forest and the strong site fidelity exhibited by members of this species.

The nesting habitat of the Clapper Rail (Rallus longirostris) is not well studied in the southeastern United States. We documented Clapper Rail nest characteristics and surrounding habitats near Brunswick on the Georgia coast. Of 159 nests found, only 29 were active. Although some nests may have been abandoned or never used, many could have been depredated. Nests were constructed farther away from tidal influences than in those populations studied in the mid-Atlantic region of the United States. Clapper Rails also tended to nest near tidal pools as frequently as tidal creeks, contrasting with other Atlantic coast studies. The greater tidal amplitude of Brunswick as compared to the mid-Atlantic coast may explain this finding. Tidal-creek nests were found farther away from, and were associated with taller vegetation near the banks of, a water source than tidal-pool nests. While nest placement differed based on habitat characteristics in this study, nest-structure morphometrics were similar between tidal-creek and tidal-pool habitats and were consistent with those found in other regions of the country.

We studied the food of nestling Rusty-margined (Myozetetes cayanensis) and Social flycatchers (M. similis) in 1998 and 1999 at Barro Colorado Island, Panama. Food samples were taken from nestlings by fecal analysis and the neck-collar method. In both species most food items were beetles, winged ants, dragonflies, spiders, and seeds of Miconia spp. Water animals (mainly backswimmers, freshwater snails, and dragonfly larvae) constituted 7.8%–13.5% of animal prey. The nestlings of the Social Flycatcher received significantly more flying insects, while the proportion of fruits and seeds was significantly higher in the diet of Rusty-margined Flycatcher nestlings. Length of animal prey varied from 4–25 mm in the Rusty-margined Flycatcher and 2–50 mm in the Social Flycatcher, and the length of fruits and seeds were 4–11 mm and 2–19 mm, respectively. The average length of animal food was larger in the Rusty-margined Flycatcher despite its slightly smaller size. The number of broods with nestlings or fledglings present in the study area was positively correlated with the abundance of fruits in the Social Flycatcher.

Male and female Stripe-backed Wrens (Campylorhynchus nuchalis) have repertoires of learned, stereotyped calls that are specific to same-sex relatives in cooperatively breeding family groups. Consequently, they are potential cues for recognizing group membership and sex during social interactions. Here I describe the use of these calls for social communication in this species. Males call much more frequently than females within a group's territory, and dominant birds call more often than subordinates. In playback experiments, males responded to their own-group calls by producing matching call types, and called at relatively high rates following simulated territorial intrusions by neighboring birds. These vocalizations appear to function primarily in maintaining social bonds within a group and in recognizing group identity during interactions with other groups.

We determined the distribution and relative abundance of resident and Nearctic-breeding, long-distance migrant grassland bird species in Córdoba province, Argentina. We sampled montane and lowland sites to determine if altitudinal differences might affect the grassland birds found there. We recorded a total of 48 grassland bird species; 38 species were recorded in the montane region and 42 species were observed on the lowland sites. Darwin's Nothura (Nothura darwinii) and Long-tailed Meadowlarks (Sturnella loyca) were restricted to the montane region. Field Flickers (Colaptes campestris) were more common in the montane region whereas Chimango Caracaras (Milvago chimango), Southern Lapwings (Vanellus chilensis), and Fork-tailed Flycatchers (Tyrannus savanna) were more common on the lowland sites. Short-billed Pipits (Anthus furcatus), Yellowish Pipits (A. lutescens), and Chaco Pipits (A. chacoensis) only occurred in the lowlands. We found that Swainson's Hawks (Buteo swainsoni) and Upland Sandpipers (Bartramia longicauda) wintered in scattered flocks in the lowlands of east and south Córdoba but that these two species did not occur in the montane grasslands. We did not find Bobolinks (Dolichonyx oryzivorus) in Córdoba. The only globally threatened species we observed was the Andean Condor (Vultur gryphus), which was recorded twice in the highlands. In general, Córdoba province is an important region for grassland birds, especially Nearctic-breeding migrants, but this area no longer supports globally threatened species other than the Andean Condor. Intensification of agricultural practices and insecticide application to control insect pests constitute the primary threats to grassland birds in this region.

High rates of Common Loon (Gavia immer) chick mortality have been documented in Wisconsin, especially on acidic lakes, but causes and timing of chick mortality are poorly understood. We modified and evaluated a subcutaneous transmitter implant technique for Common Loon chicks using wild and captive reared chicks. Results indicated that behavior, growth, energy expenditure, and survival did not differ significantly between chicks marked with miniature transmitters (mass 0.76 g, representing <0.8% of body mass at hatching) and unmarked chicks.

We lured White Ibises (Eudocimus albus) to trap sites with decoy plastic flamingos and captured them with a rocket net or mist nets. Our ability to attract ibises to a site (and consequently our capture success) was affected by vegetation height and water depth but not by decoy numbers or their arrangement. Both the rocket net (37 ibises) and mist nets (97 ibises) caught birds. The number of birds captured per day was the same for both methods, but the rocket net trap captured more birds per set than did mist nets. Because mist nets were easy to reset we captured 1–2 birds per set multiple times in one day with mist nets. We preferred mist nets over rocket net traps because mist nets allowed for shorter bird processing times, greater ease of set up, and fewer safety considerations for transport and operation of the trap. Also, rocket nets required more equipment and expense. Although we discouraged other species from landing at a trap site, there was evidence that these techniques may also be useful for capturing other wading birds.

We describe a method for measuring gut passage time and seed dispersal distance for a large terrestrial frugivore. We attached temperature data loggers to radio transmitters in baits that were ingested by free-ranging cassowaries. The resulting data yielded information on how fast the unit passed through the gut (3–4 h) and how far they were moved (240–325 m), an analog for dispersed seeds. Additionally, the data loggers revealed that cassowaries reingest fecal matter, the first observation of coprophagy in wild cassowaries.