We studied the breeding performance of very old Common Terns (Sterna hirundo) at Bird Island, USA (41°40′N, 70°43′W), in 1999. We studied birds aged ≥18 yr, comprising the oldest 5% of the birds breeding at this site. We located 24 of these old birds and measured their breeding performance, including laying dates, clutch sizes, egg masses, hatching success, chick growth, chick survival, and overall productivity. We compared their performance with that of several reference groups, including a date-matched group of young birds aged 6–9 yr and date-matched birds of all ages. Breeding performance declined with laying date in all groups. The old birds were more successful in raising chicks than any of the reference groups. Within the group of old birds, breeding performance remained high or improved with age, even after controlling for effects of laying date. Males and females were represented equally among the group of old birds; there was no evidence that performance was higher among old males or old females. If the Common Terns at this site experience any senescent decline in breeding performance within their 20–25 yr lifespan, this must be offset either by increased reproductive effort or by selective survival of high quality individuals.

Rates of cavity excavation by Red-cockaded Woodpeckers (Picoides borealis) were examined from 1983 to 1999 on the Angelina National Forest in east Texas. We compared the rate of natural cavity excavation between 1983 and 1990 (before artificial cavities were available) with the rate of cavity excavation between 1992 and 1999, a period when artificial cavities were regularly installed within active woodpecker cavity-tree clusters. Our comparison was restricted to cavity-tree clusters in longleaf pine (Pinus palustris) and loblolly (P. taeda)-shortleaf (P. echinata) pine habitats where woodpecker groups were present for the entire period between 1983 and 1999. Excavation rate of new cavities was significantly higher in longleaf pine habitat when artificial cavities were not available than during the subsequent period when artificial cavities were provided in all active cavity-tree clusters. In loblolly-shortleaf pine habitat, we did not detect a significant difference in the rate of new cavity excavation between the periods before and after the use of artificial cavities. We attribute the difference in results between habitats to a relative scarcity of cavities in loblolly-shortleaf pine sites due to a higher bark beetle-induced cavity tree mortality.

Measurements of food availability for avian insectivores are desirable, but are complicated by the range of microhabitats insects occupy and the difficulty of comparing non-standard techniques across studies. We describe an efficient method for sampling wood-boring beetle larvae, an important food of many woodpeckers, beneath the bark of fire-killed trees. The method involves taking two 225-cm² bark samples from each tree, and provides enough information to rank most trees by relative wood-borer abundance. At two sites in the northern Rocky Mountains, we tested the reliability of this method by comparing its results to those of a more intensive sampling scheme. For 65 trees of four species, we collected eight bark samples at two different heights, 1.7 m and 6 m, and compared correlations between the smaller, ground-based sampling scheme (two bark samples) and the larger, eight-sample effort. With one exception, correlations for individual tree species ranged from 0.79 to 0.95, indicating that the smaller sample gave rankings of insect abundance comparable to those of the larger sample. Correlation strengths differed between sites, suggesting that the larger sample could be employed at future sites to fine-tune the smaller sampling scheme. Correlations for ponderosa pine (Pinus ponderosa) at one site were very low, suggesting that wood-borers may colonize ponderosa pine in a manner different from the other tree species studied. The strong correlations produced by this test indicate that, with limited effort and training, even small field crews (e.g., two workers) can use this method to rank the foraging resources contained in dead trees.

We used a three-year point-count data set from Hoosier National Forest, Indiana, to evaluate alternative point-count sampling strategies for detecting songbird declines. Repeated-measures ANOVA indicated that mean abundance estimates increased with increasing count radius (P < 0.0001, each species), and coefficients of variation (CVs) decreased. Mean abundance estimates increased with longer count duration (6-, 8-, and 10-min) for only two of 13 species, and CVs did not necessarily decrease. The power to detect a 5% annual population trend increased with more survey points, more visits per point, and more years of surveys. Managers can use observer time most efficiently by employing counts of short duration. Counts using a larger radius will reduce CVs and therefore provide potentially better annual estimates of abundance and power to detect changes over a period of years. The design of the study and nature of the variability in bird abundance will determine whether increasing the number of points, or the number of visits per point, will have greater effect on power to detect a population trend.

During March–June 2000 we evaluated the use of call-response surveys to monitor breeding Yuma Clapper Rails (Rallus longirostris yumanensis) at the Ciénega de Santa Clara, Colorado River Delta, Sonora, Mexico. We assessed the effect that time of day, stage of breeding season, and number of survey periods had on the average number of rails detected at a station. Conducting call-response surveys resulted in a significant increase in the number of detected rails and reduced the coefficient of variation of the average number or rails per station, which increases the statistical power to detect population trends. Using this technique also appears to reduce the variation of rates of responses by rails through the breeding season when compared to passive listening. There was no difference between the number of rails detected during morning and afternoon surveys. The established protocol developed by the U.S. Fish and Wildlife Service for Yuma Clapper Rail surveys is adequate for monitoring, and it should continue to be implemented on a yearly basis at the Ciénega de Santa Clara and other wetlands of the Colorado River Delta in Mexico.

We conducted intensive surveys of breeding and wintering Snowy Plovers (Charadrius alexandrinus nivosus) in San Diego County from 1994 through the winter of 1999. We found Snowy Plovers using 11 sites within the study area for nesting and at least 18 sites were used during winter months. Estimated breeding populations of Snowy Plovers within San Diego County fluctuated among years, and males always outnumbered females; fewer than 325 Snowy Plovers were present during any breeding season. Two sites consistently supported 65% of nesting pairs during this study, both at military installations. Nesting sites with fewer than five breeding pairs were unlikely to produce fledglings. Nest success over the entire area ranged from 50–58% and reproductive success was on average fewer than 0.5 fledglings produced per adult plover. Approximately 227–367 Snowy Plovers wintered within San Diego County from 1995–1999, which is within the range of winter population estimates from the mid-1980s. Neither breeding nor wintering numbers of plovers in San Diego County have increased since the 1980s, and it is unlikely that populations can increase given the low rates of reproduction. In addition, the concentration of most nesting pairs at a few sites makes this population more vulnerable to local extirpation.

Greater Rheas (Rhea americana) are ground-nesting birds that have high rates of nest desertion commonly associated with egg predation. We studied whether male Greater Rheas selected concealed sites to decrease detectability of their nests. We analyzed the spatial distribution of nests and compared the microhabitat characteristics of nest sites vs. sites selected at random, and sites of successful nests vs. sites of deserted nests. We also used experimental nests (nests without male attention) to assess whether egg losses were associated with the microhabitat characteristics of the nest site. The distribution of nest sites differed significantly from a random pattern, and nest sites had a higher percentage of shrub cover, a lower percentage of grass cover, and a higher concealment (low overall visibility) than sites selected at random. However, none of the microhabitat characteristics that we analyzed were associated with nest failure or the rate of egg loss. Experimental nests that were more visible tended to suffer higher and faster egg predation than less visible ones. Our results indicate that Greater Rheas selected concealed sites for nesting, but they did not get any apparent benefit for selecting these sites. We propose that habitat alteration and the type of predation that this species suffers at present may have reduced the benefits of selecting concealed sites for nesting.

Common Terns (Sterna hirundo) typically favor nest sites with 10–30% vegetative cover, and cover >30% may decrease nest success. Vegetation manipulations were performed in summer 1998 on Lime Island, Michigan, to determine if vegetative structure affects nest success of Common Terns. Three treatments (partial and complete herbicide and a control) were randomly assigned to 5 × 5-m plots. Our results suggest that Common Terns on Lime Island have the greatest nest success in areas that contain moderate amounts (about 40%) of total standing vegetation cover and litter cover (about 50%) that were associated with the partial herbicide areas. Although the greatest number of Common Tern nests were located in areas with 10–30% standing cover and >65% litter cover (complete herbicide), those areas had the lowest nest success. Researchers should not disregard the importance of areas that typically support fewer nests in greater amounts of standing vegetation cover when evaluating the nest success of Common Terns.

Banded Roseate Terns (Sterna dougallii) trapped on nests in the Azores illustrate that, during the nonbreeding season, birds from the Azores are found on the coast of Africa in groups of Roseate Terns from northern Europe and on the coast of South America with birds from the northeastern U.S. and the Caribbean. One Roseate Tern, probably originally banded on a nest in a western Atlantic colony, suggests the possibility of gene flow between these colonies and the Azores.

Optimal foraging theory predicts that individuals should resort to kleptoparasitizing food when the net energy obtained from this behavior is greater than that gained from searching for food conventionally. We studied kleptoparasitism in the Cattle Egret (Bubulcus ibis) in southwestern Spain. Intraspecific kleptoparasitism in Cattle Egrets was rare. We recorded this behavior only when egrets foraged in large flocks and when potential victims had captured large prey items. In addition, we observed kleptoparasitism in feeding areas with high food availability. Food intake rates for both aggressor and victim, prior to the attack, were greater than that of undisturbed individuals. Victims with defensive behavior maximized their feeding rate by capturing the largest prey items and expending the least energy. Kleptoparasites' attack success depended mainly on the degree of the victim's resistance to releasing prey, which in turn was apparently determined by the victim's foraging success and condition. We conclude that intraspecific kleptoparasitism in Cattle Egrets is not an optimal foraging behavior, but rather is to establish the social status of dominant individuals within a foraging flock.

Forced regurgitation by oral administration of tartar emetic has been used frequently to examine avian diets because it does not require killing birds directly, but indirect (delayed) mortality by this technique is not well studied. We examined the effects of tartar emetic on re-sighting rates of insectivorous migratory songbirds in Jamaica during the non-breeding season. The re-sighting rate of Black-throated Blue Warblers (Dendroica caerulescens) experimentally treated with tartar emetic was significantly lower than for control birds. The re-sighting rates of American Redstarts (Setophaga ruticilla), Black-and-white Warblers (Mniotilta varia), and Prairie Warblers (Dendroica discolor) treated with tartar emetic were also lower than those of birds that were banded and released without treatment. Pre-release mortality rates were low (<3%), but two treated Black-throated Blue Warblers were found dead up to 22 h after release. Our results suggest application of tartar emetic is an effective but invasive method for collecting diet samples from birds. Researchers should consider alternatives, and future administration of tartar emetic should be conducted conservatively and with acknowledgment of its occasionally lethal results.

We describe a system for photographing the longitudinal and transverse planes of bird eggs that improves accuracy of measurements of egg size and increases the speed of data collection. The proposed system consists of a flat support, with a few small holes where eggs are lodged. The system was tested using Japenese Quail (Coturnix coturnix) eggs, and the accuracy and repeatability of the photographic method were high.

We investigated the incubation behavior of a ground-nesting shorebird, the Snowy Plover (Charadrius a. alexandrinus) by developing a transponder system that recorded the identity of parents on their nest over 24 h. The system consisted of a small chip glued on the tail of the parent, an antenna that was buried under the nest, and a recording device that was buried nearby. The transponder system was both accurate and reliable, since only 0.2% of records were false. The records of the transponder system were augmented by visual observations, and these data were analyzed by randomization tests. We found strong daily incubation routines: females incubated during the day, whereas males incubated mostly at night. Overall, the females spent significantly more time incubating the nest (11.3 h (median)/day) than the males (9.4 h/day). We discuss several hypotheses for the observed daily incubation routines of the sexes, and propose experimental studies to test these hypotheses.

Forty-seven wild female Lesser Scaup (Aythya affinis) were marked with nasal markers and radio transmitters (implanted subcutaneously on the back) just prior to breeding near Yellowknife, Northwest Territories, in 1999 and 2000. Retention rates of both marker types were evaluated, and their effects on specific behavior categories were assessed by comparison of marked birds with unmarked control birds. Significant effects of nasal markers on behavior were detected; females often removed vegetation from nasal markers after diving, and consequently marked females tended to shake their head more frequently than unmarked birds. No nasal markers were lost during the study. Five females lost radios, producing an average retention time of 39 d. Daily retention rate was 0.997, being 0.85 when extrapolated to 60 d. The survival rate of 42 females radio-tracked consistently was constant for six 7-d intervals, suggesting no immediate adverse effect on survival. Because the technique is invasive, use of subcutaneous transmitters may not be appropriate for all applications, but it could be a preferred alternative to other transmitter-attachment methods for short-term tracking of waterfowl.

New information on the interactions among Shiny Cowbirds (Molothrus bonariensis) and 12 host species in Argentina is presented. Observations and experiments suggest that Brown Cacholotes (Pseudoseisura lophotes) remove cowbird eggs from their nests. I present data on care and provisioning of Shiny Cowbird chicks by nine species (including five icterids), all new or rarely reported in this role in host catalogs. Fifteen of 19 (79%) of the nesting Argentinian icterids are reported as Shiny Cowbird hosts, and seven (37%) are known to rear chicks of this parasite to fledging (effective hosts). Saffron-cowled Blackbirds (Xanthopsar flavus) are frequent effective hosts but now have a restricted distribution. The Pale-breasted Thrush (Turdus leucomelas) was an important effective cowbird host in the area of Iguazú falls, and the Diuca Finch (Diuca diuca) is a frequent effective host in the Argentinian Patagonia.

We used a modified fish trap called a “single strip Dutch sleeve” to capture small rails in Spain. During 94 trap-days, we captured 29 individual Water Rails (Rallus aquaticus), three Spotted Crakes (Porzana porzana), and nine Common Moorhens (Gallinula chloropus). Use of bait such as fruits, vegetables, or cat food increased capture rate by 93%, whereas inclement weather (heavy rain or wind) decreased capture rate. We had greater rates of capture and recapture compared to other studies using different methods. Advantages include ease of transport and placement, low injury rates to birds, the possibility of simultaneous captures, and a wide spectrum of target species. As improvements, we propose the use of playback rail vocalizations to increase capture of individuals and species, and the use of rigid, inaccessible receptacles to protect captured rails from predators.