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Nest defense represents a parental strategy to maximize fitness by enhancing prospects of offspring survival. We used a taxidermic mount of a nest predator to measure nest defense of Eastern Kingbirds (Tyrannus tyrannus) at Malheur National Wildlife Refuge in southeastern Oregon in 2003 and 2004 to test the hypotheses that intensity of nest defense (1) was individually repeatable, (2) differed between males and females, and (3) predicted nest success. We also predicted that (4) intensity of defense would increase with age and number of young, but decline over the breeding season. Intensity of nest defense was significantly repeatable for male kingbirds. Male response was twice as strong as female response during incubation and the nestling period, but nest success was independent of defense scores of males and females. Simple paired comparisons suggested female responses did not change between incubation and the nestling period, whereas males tended to defend nestlings more vigorously than eggs. Multivariate analyses demonstrated strong individual differences were the main source of variation in nest defense. Intensity of nest defense by males and females increased with age of young, declined seasonally, but was not related to number of young. Kingbird nest defense is a repeatable behavior that differs between males and females and, as predicted by parental investment theory, nests of the greatest value (older young and earlier broods) were defended most aggressively.
We assessed mate fidelity, nest-box fidelity, and breeding dispersal distances of American Kestrels (Falco sparverius) nesting in boxes in southwestern Idaho from 1990 through 2006. Seventy-seven percent of boxes had different males and 87% had different females where nest-box occupants were identified in consecutive years. High turnover rates were partly a result of box-switching. Forty-eight percent of males and 58% of females that nested within the study area in successive years used different boxes. The probability of changing boxes was unrelated to gender, nesting success in the prior year, or years of nesting experience. Breeding dispersal distances for birds that moved to different boxes averaged 2.2 km for males (max = 22 km) and 3.2 km for females (max = 32 km). Approximately 70% of birds that nested in consecutive years on the study area had a different mate in the second year. Mate fidelity was related to box fidelity but not to prior nesting success or years of nesting experience. Mate changes occurred 32% of the time when the previous mate was known to be alive and nesting in the area. Kestrels that switched mates and boxes did not improve or decrease their subsequent nesting success. Kestrels usually switched to mates with less experience and lower lifetime productivity than their previous mates. The costs of switching boxes and mates were low, and there were no obvious benefits to fidelity. The cost of “waiting” for a previous mate that might have died could be high in species with high annual mortality.
Estimates of community attributes such as species richness, local extinction, and turnover are critical when evaluating ecological restoration efforts. Estimates of species richness based on counts can be biased by variation in the probability of detection among different species. We quantified the effects of livestock exclusion on riparian bird communities using mark-recapture models to account for variation in species detection rates. Specifically, we estimated species richness and other community parameters for fenced and grazed sites with robust design models where closed-captures were treated as mixtures, and then used transition rates to calculate derived vital rates for avian communities. Estimates of species richness based on unadjusted counts were correlated with estimates from robust design models, but counts failed to detect important temporal changes in species richness. Estimates of species richness from robust design models increased at fenced and grazed sites over an 8-year period, but community vital rates were unaffected by cattle exclusion. We examined qualitative changes in abundance of birds in four nesting guilds, and concluded that temporal changes may have been driven by regional dynamics in avian communities. Our mark-recapture analysis allowed us to compare standardized estimates of community parameters between habitats, observers, and time periods after accounting for variation in detection rates. Robust design models are a useful tool that will facilitate accurate assessments of community dynamics following future restoration efforts.
St. John, U.S. Virgin Islands, is one of the most forested islands in the West Indies and provides an opportunity to conserve both resident birds and wintering neotropical migrants. We conducted double-observer point counts of landbirds in December 2005 and 2006 in Forest Inventory and Analysis (FIA) plots and National Park Service (NPS) trails in Virgin Islands National Park (VINP) to assess population trends of birds in subtropical dry and moist forests. We recorded 2,270 individual birds representing 35 species at 150 point count stations in 2005, and 3,092 individuals of 32 species at 143 of these stations in 2006. The increase in birds per point from 2005 (15.1) to 2006 (21.6) was due to resident species, 17 of which were recorded more frequently in 2006. The 17 species of neotropical migrants composed 11.8% of all registrations in 2005 and 2006. Subtropical moist and dry forest habitats differed strongly in vegetation characteristics and plant species, but no species of birds exhibited a strong affiliation with either habitat type on FIA plots. Data from NPS trails showed that most migrant species were detected more often in moist, mature forest. The resident Bridled Quail-Dove (Geotrygon mystacea) also was correlated with mature forest. Plant and bird species co-occurrence with positive correlations that may carry a signal of preferred frugivory included Guettarda odorata (Rubiaceae) with Bridled Quail-Dove, and Myrciaria floribunda (Myrtaceae) with Pearly-eyed Thrasher (Margarops fuscatus). Migrant species did not exhibit strong long-term changes in relative abundance since founding of VINP in 1957, but four open-country resident species declined significantly between 1957 and 2006 as the forest matured. Forest maturation should continue on St. John, yielding a bright future for most of its landbirds barring catastrophic hurricanes, pathogens, or invasive plants.
We provide an inventory of the avifauna of the Pongos Basin, northern Amazonas Department, Peru based on museum specimens collected during expeditions spanning >60 years within the 20th century. Four hundred and thirty-eight species representing 52 families are reported. Differences between lowland and higher elevation avifaunas were apparent. Species accounts with overviews of specimen data are provided for four species representing distributional records, two threatened species, and 26 species of Nearctic and Austral migrants, of which six are considered probable migrants.
The abundance of wood cavities is thought to be a limiting factor for bird species that depend on these cavities for nesting. Thus, it is expected that number of cavity adopters correlates with number of cavity excavators across communities. We used available published data to compare composition and richness of cavity adopters and cavity excavators across seven forest localities in Costa Rica. Species richness and composition of cavity excavator and cavity adopter bird assemblages varied among the seven forests. Species composition of excavators and adopters was more similar between nearby localities and between localities with similar forest types. Richness of wood-cavity adopters (using mostly cavities created by excavators) tended to increase with richness of excavators. The lack of association between cavity adopters and cavity excavators in some localities may be compensated by high abundance of a few species of excavators. The abundance of adopters and their dependence on forested habitats and on cavities excavated by woodpeckers varied largely across localities.
Accurate estimates of Black-backed (Picoides arcticus) and Hairy Woodpecker (P. villosus) nests and nest survival rates in post-fire landscapes provide land managers with information on the relative importance of burned forests to nesting woodpeckers. We conducted multiple-observer surveys in burned and unburned mixed coniferous forests in Oregon to identify important factors influencing detection rates of woodpecker nests. We found 21 Black-backed Woodpecker nests and 38 Hairy Woodpecker nests in burned forest, and three Hairy Woodpecker nests in unburned forest. Competing models of detection probability in Program MARK indicated that nest-detection probability differed by nest stage. We found no evidence to indicate that detection rates of nests were associated with survey timing during the nesting season. Raw nest counts in burned coniferous forests may underestimate nest numbers, especially for nests in early stages of development. Black-backed Woodpecker nests were slightly more detectable than those of Hairy Woodpeckers in burned forests, and observers may differ in their abilities to detect nests.
Lewis's (Melanerpes lewis) and Red-headed Woodpecker (Melanerpes erythrocephalus) breeding ranges overlap slightly, but co-occurrence within habitats is thought to be rare because of niche similarity. Our objectives were to examine factors that allowed for co-existence in two burned pine (Pinus ponderosa) forests in the Black Hills, South Dakota. We monitored 53 Lewis's and 38 Red-headed Woodpecker nests between 2002 and 2005, and compared clutch initiation dates and nest-site selection. Clutch initiation dates did not differ between species for 3 of 4 years. We compared multiple habitat factors surrounding nests of the two species, and only tree and snag densities differed between Red-headed Woodpecker nest sites (65.1 ± 5.78 stems/ha) and those of Lewis's Woodpeckers (48.5 ± 6.06 stems/ha). These results are consistent with the foraging techniques used by the two species. We suggest that habitat partitioning is an important mechanism of coexistence for these two species, but also recommend further research on their foraging strategies.
We investigated variation in foraging effort (horizontal distance traveled/number of foraging movements), percent of aerial hawking foraging movements (attempted capture of prey from air), mean perch height of sally initiation (height of perches from which sallies are initiated), and mean sally distance (distance from perch to prey) of non-breeding Eastern Phoebes (Sayornis phoebe) as a function of weather and habitat conditions. Only ambient temperature significantly correlated with foraging effort (r = −0.32, P = 0.02), indicating Eastern Phoebes expended more effort in search of prey under colder conditions. Both ambient temperature and distance to nearest water source significantly correlated with aerial hawking; however, the model containing only ambient temperature best explained variation in aerial hawking (r = 0.38, P = 0.008), indicating Eastern Phoebes attempted to hawk more prey from air at warmer temperatures. Mean perch height of sally initiation did not correlate (P > 0.05) with ambient temperature, wind speed, or vegetative density and dispersion. Mean sally distance did not correlate (P > 0.05) with ambient temperature, wind speed, or mean perch height of sally initiation but the natural log of sally distance correlated inversely (r = −0.48, P = 0.0004) with vegetative density and dispersion. The manner in which Eastern Phoebes alter foraging behaviors under varying environmental conditions, in conjunction with physiological adaptations, may be an important factor allowing this species to winter at higher latitudes than most other North American tyrant flycatchers and forage in multiple habitats.
Perch-sites are a necessary component of Loggerhead Shrike (Lanius ludovicianus) foraging habitat, yet little is known about the influence of perch characteristics on perch use. We hypothesized that Loggerhead Shrikes would selectively forage from taller, bare perches with less foliar obstruction to potentially increase prey detection rates. Shrikes in our study area foraged from trees ∼10% taller than those available and on dead or partially dead trees more often than expected (P = 0.005). Deciduous trees with a leafy canopy in summer were more likely to be used when bare in winter. Removing all obstacles to prey detection did not increase perch preference. Shrikes perched more often and for more total time on constructed artificial perches surrounded by dead branches (50% of used; 166 sec/territory) than on treatments with leafy branches (14%; 32 sec) or no branches (36%; 50 sec). Our results suggest trees that are more useful are those with a good view of potential prey and which also provide cover from potential attacks by predators. This study demonstrates the relevance of perch-site characteristics to Loggerhead Shrike foraging habitat and we suggest consideration for perch-site characteristics in future conservation efforts.
Little is known about how landbirds use urban habitats as migratory stopovers despite increasing urbanization in North America and the importance of the migratory period to annual survival of birds. I examined 15 years of autumn stopover data for three species of migratory Catharus thrushes from an urban natural area in metropolitan Detroit, Michigan, USA. The majority of birds were in good condition on first capture with 59% having more than a just a trace of fat, a higher proportion than reported for passerines at other fall stopover sites. Condition was similar among species, and there was little difference in fat class or mass between age groups. A linear regression of the condition of each bird at first capture and time of capture indicated positive diurnal mass gains in two species and mass loss in the third. Fourteen percent of thrushes banded were recaptured. Lean birds were not more likely to be recaptured than fatter birds and, among recaptured birds, there was no difference in stopover period or mass or fat increases between young and adults. Seventy-nine percent of recaptured birds gained mass, and mass and fat class increases were significant for all species. These results are discussed in view of the high prevalence of non-native fruit resources and rates of human disturbance at the study site.
Many species of temperate migrant birds are abundant in winter in the southeastern United States, but little is known about fidelity of migratory species to wintering areas. Mist netting was conducted at Rock Springs Run State Reserve in Orange County, Florida during the non-breeding season from 1997 to 2002. We quantify the first records of winter site fidelity for Gray Catbird (Dumetella carolinensis), House Wren (Troglodytes aedon), and Orange-crowned Warbler (Vermivora celata). We also document the first known winter returns of Blue-headed Vireo (Vireo solitarius) and Ovenbird (Seiurus aurocapilla) in temperate winter areas. Many site faithful birds exhibited over-winter site persistence by being recaptured many times throughout the winter (over 4 weeks), suggesting these birds are site faithful within and between years. Patterns of returns and over-winter site persistence followed trends expected from life history characteristics for most species.
We studied building characteristics and landscape context to predict risk of migratory birds being killed by colliding with sheet glass on Manhattan Island, New York City, New York, USA. Trained volunteers monitored 73 discrete building facades daily from the Upper East Side to the southern tip of the Island during autumn 2006 and spring 2007 bird migratory periods using a consistent and scientifically valid search protocol. We recorded 475 bird strikes in autumn 2006 and 74 in spring 2007 of which 82 and 85%, respectively, were fatal. Most building and context variables exerted moderate influence on risk of death by colliding with glass. We recommend a suite of building characteristics that building designers can use to reduce risk of collisions by minimizing the proportion of glass to other building materials in new construction. We suggest that reduction of reflective panes may offer increased protection for birds. Several context variables can reduce risk of death at glass by reducing ground cover, including changes in height of vegetation, and eliminating shrubs and trees from areas in front of buildings. We estimated 1.3 bird fatalities per ha per year; this rate extrapolates to ∼34 million annual glass victims in urban areas of North America north of Mexico during the fall and spring migratory periods. Clear and reflective sheet glass poses a universal hazard for birds, specifically for passage migrants in New York City, but also representative and comparable to growing urban areas worldwide.
We assessed association of Northern Bobwhites (Colinus virginianus) with surface water (natural and artificial) in the semi-arid Texas Panhandle during May–September 2001–2003. The difference between mean Euclidean distances of nest locations (n = 33) and random points to nearest surface water was −107.8 m (SE = 17.4, 95% CL = −142.7 to −72.9) indicating that nest locations were closer to water than expected by chance. Non-nesting birds appeared to associate with surface water during summer (May–Aug) based on differences between location distances of 83 bobwhites (1,408 locations) and random-point distances to nearest surface water (x̄ ± SE = −62.4 ± 17.0 m, 95% CL = −96.4 to −28.4). Our results provide evidence that bobwhites may associate with surface water in the semi-arid Texas Panhandle.
We investigated variation in morphology of American Dippers (Cinclus mexicanus) in the Chilliwack River watershed, British Columbia in relation to gender, age and migratory habit. Male dippers had linear dimensions that were 2–9% longer and, on average, were 16% heavier than females. Adults (AHY) were the same structural size as yearlings (HY). Yearlings, however, had shorter and more rounded wings than adults providing support for the hypothesis that an increased vulnerability to predation may lead to selection for traits that improve take-off performance and maneuverability. Yearlings also had shorter tails suggesting other selective pressures shape tail morphology. Dippers in this population may be sedentary or migrate short distances to breed at higher elevations. We found no evidence that wing or tail morphology varied with migratory habit or that sedentary dippers, that have higher reproductive success, are larger or heavier than migrants.
We used field and museum data to describe timing of flight feather molt in the endangered Hawaiian Moorhen (Gallinula chloropus sandvicensis). We evaluated 80 adults captured a total of 107 times at two study sites on Oahu from April 2005 to August 2007. Eighty-five of the birds were not molting, 13 had abraded remiges, and eight of the nine molting adults examined were simultaneously replacing their primaries, secondaries, and upper and lower wing coverts. We also scored molt for 28 Hawaiian Moorhen specimens from three museum collections, but no birds were molting. Molt in Hawaiian Moorhens, which lasts about 30 days, was not synchronous across individuals with molting birds recorded from June to September in the field. We observed non-molting individuals throughout the year including birds we captured and museum specimens. Molting and non-molting birds had similar body condition, as defined by mass/tarsometatarsal length. The flightless period during molt, which likely lasts about 25 days, may increase predation risk, a serious concern in Hawaii where introduced terrestrial predators pose a major threat to moorhen populations.
We studied the habitat association of Band-tailed Antbirds (Hypocnemoides maculicauda) in four forest types in the Brazilian Pantanal between 1999 and 2006. Birds were sampled with standardized mist nets during 20 months and point count censuses during 14 months. Band-tailed Antbirds exhibited a preference for seasonally flooded forests (Landi and Cambarazal) with no capture or detection in drier forests (Cordilheira and Carvoeiro), even during the wet season. We found no evidence of regular local movements between different forest types. The 21 recaptures were normally in the same forest patch as capture, indicating strong site fidelity and defense of year-round territories. The 10 nests observed were pouch shaped and constructed with plant fibers; each contained two eggs. Nests were found between January and April when the Pantanal is flooded. The unusual breeding season of the Band-tailed Antbird appears to be closely associated with the flooding regime.
Few nests and eggs for the genus Atlapetes (Emberizinae) have been described. I describe the first nest and egg for the Pale-naped Brush Finch (Atlapetes pallidinucha). The nest was a bulky open cup similar to those for other species in the genus Atlapetes, but differed from that of A. melanocephalus. The egg resembled those of A. albinucha, A. leucopis, and A. latinuchus demonstrating the variability among the genus. Nesting appears to be associated with the second peak of rains of the year.
I report previously undocumented “fanning: and “crash-diving” behavior of the Least Grebe (Tachybaptus dominicus). I speculate that “fanning” may be used to control egg temperature, and may be related to “rearing” and “wing-quivering” behavior known for some South American grebes. I also summarize information on nests, clutch size, and egg-covering by Least Grebes in the Lower Rio Grande Valley of south Texas.
Eggshell thickness is commonly used as an indicator of habitat quality and effects of environmental pollution on avian reproduction. We present the first data available on eggshell thickness for Red-legged Partridge (Alectoris rufa) in Spain. We compared eggshell thickness between eggs collected in an agricultural area (wild eggs) and eggs from game farms (farm eggs). Wild eggs had shells significantly thicker (x̄ = 0.32 mm, n = 74) than farm eggs (x̄ = 0.28 mm, n = 89), despite game farm partridges being fed a diet rich in calcium and not exposed to agricultural pollutants. Eggshell thickness did not affect hatching success of wild partridges, and population decline observed in this species cannot be linked to reduction in egg viability due to eggshell thickness.
Clutch reduction (the disappearance of 1 or more eggs) is often reported in studies examining avian reproductive success and has typically been attributed to nest predation. We recorded clutch reductions at 20 (11%) of 188 Piping Plover (Charadrius melodus) nests at Chaplin Lake, Saskatchewan from 2002 to 2004. Partial clutch reductions were initially assumed to be the result of predation. However, all egg disappearances at three nests we monitored using video cameras were due to accidental removal by incubating parents. Our observations suggest that accidental removal may occur more frequently than expected in alkaline environments, and are likely misclassified as losses due to predation.
Results of simulated brood parasitism on five Gray Jay (Perisoreus canadensis) nests suggest acceptance of model Brown-headed Cowbird (Molothrus ater) eggs. This finding is contrary to results of experimental parasitism on four other species of jays, also with little or no recent history of parasitism, which eject cowbird eggs. Given that Gray Jays nest in the boreal forest and earlier in the season than cowbirds initiate breeding, it may be that neither Gray Jays nor their congeners have been parasitized regularly in their evolutionary histories, which may explain acceptance of cowbird parasitism.
On 27 May 2007 I discovered two Brown-headed Cowbird (Molothrus ater) eggs in an artificial nest in a wooded fence line on the Tallgrass Prairie Preserve, Osage County, Oklahoma. The artificial nest was one of 20 placed along a transect 10 days earlier and baited with two infertile Blue Quail (Coturnix adansonii) eggs during a study on nest detection and predation. Brown-headed Cowbird parasitism of artificial open-cup nests in the absence of host nesting activity is rare, but has been reported. This occurrence of superparasitism represents the first record wherein more than one cowbird egg was deposited in an artificial nest, indicating that either a single female repeatedly parasitized the nest, or that a second female contributed an egg to the previously parasitized nest.
Northern Mockingbirds (Mimus polyglottos) are known to reject parasitic eggs at an intermediate rate. However, proximate mechanisms of rejection remain unexplored. Our objectives were to examine the rejection behavior of Northern Mockingbirds in northeast Louisiana, explore if nesting date or egg color of parasitic eggs influence the rate that Northern Mockingbirds reject Brown-headed Cowbird (Molothrus ater) eggs, and compare results to those of previous studies. Northern Mockingbirds rejected 68% of artificial eggs. Early nesting individuals rejected 50% of the model eggs and late nesters rejected 82%. Early nesting Northern Mockingbirds rejected 72% of light eggs compared to 27% of dark eggs. Color of the parasitic egg and date of parasitism may influence rejection rates of Northern Mockingbirds.
The Island Loggerhead Shrike (Lanius ludovicianus anthonyi) is classified as a species of special concern by the California Department of Fish and Game. We conducted a breeding bird census of Loggerhead Shrikes on Santa Cruz Island in 2006 based on potential shrike habitats identified using remote sensing. Census results for 2006, along with additional findings, constitute the first quantitative and replicable assessment of the subspecies' status. Population size is <30 birds with 12 on Santa Cruz Island and 15 on Santa Rosa Island. These observations, coupled with comparable surveys on other northern Channel Islands, provide the basis for a species and habitat conservation management plan.
We describe long-term pair bonds in the endangered Laysan Duck (Anas laysanensis), a dabbling duck endemic to the Hawaiian Archipelago. Individually marked birds were identified on Laysan Island between 1998 and 2006 (n = 613 marked adults). We recorded pair bonds while observing marked birds, and documented within and between year mate switches and multi-year pair bonds. Twenty pairs banded before 2001 had stable pair bonds lasting ≥5 years with a maximum enduring pair bond of nine breeding seasons. Understanding reproductive strategy, including mate retention, would aid conservation planning and management efforts for the Laysan Duck. Further study is needed to characterize the social system of this endangered species.
We monitored two migratory oriole species, Baltimore (Icterus galbula) and Orchard (I. spurius) orioles, for information on return rate and pair fate over 4 years. The return rate after migration for Baltimore and Orchard orioles was low (38 and 35%, respectively). Pairs were more likely to dissolve due to non-return of one or both members than they were to reunite or change mates. Pair members infrequently returned to the study site and previous pairs had little opportunity to reunite in the next year. Birds with non-returning mates appeared to take advantage of the first available mating opportunity instead of waiting for the return of their previous partners.
We monitored return rates of 114 breeding Henslow's Sparrows (Ammodramus henslowii) on mowed and unmowed areas on a reclaimed surface mine during seven breeding seasons. We observed 15 returns (13%) among 10 individuals (9%), all on unmowed areas. No individuals banded on mowed areas were observed in subsequent years on the same areas. Return rates increased slightly when hatching year birds were excluded. No individuals banded during their hatching year were subsequently seen again. Three of 10 returning individuals were observed during multiple years. These observations support previous findings that reclaimed surface mines provide adequate nesting habitat for Henslow's Sparrows. Early-season mowing as a management strategy should be used with care.
Sprague's Pipit (Anthus spragueii) is a threatened grassland songbird that has been described as one of the least known species in North America. We attached radio transmitters to 19 Sprague's Pipit nestlings in south-central Saskatchewan in 2004 and 2005 as part of a study to quantify post-fledging movements. Eleven juveniles died before leaving the nest (58%) and five survived for at least 9 days. Predation was the most common cause of mortality of young pipits both before and after fledging. Distances moved between days steadily increased but fledglings typically remained within 100 m of their nest during the first week post-fledging. Movement by fledglings after the first week were typically >100 m.
We monitored one female hack-released Osprey (Pandion haliaetus) across her lifespan and identified her migration routes over a 4-year period (2002–2006) using satellite radiotelemetry. We documented the recruitment of this bird into the breeding population and her lifetime reproductive success. This Osprey was raised at Big Muskego Lake in southeast Wisconsin, wintered at Lake Bayano in Panama (3,877 km south-southeast [163°] of Big Muskego Lake), and nested near St. Paul, Minnesota (4,183 km north-northwest [343°] of Lake Bayano and 446 km northwest [300°] of Big Muskego Lake). The lifespan of this female was 5 years, 5 months, and her lifetime reproductive success was three young over a period of 3 years, 2005–2007, as a breeder. Migration routes of this individual Osprey changed over her lifespan; these changes may have been influenced by weather.
Red-shouldered Hawks (Buteo lineatus) typically line their nests with fresh branches of coniferous and deciduous trees. We recorded all species of green material present in 63 nests from 2003 to 2005 in suburban Cincinnati in southwestern Ohio, and in 35 nests in Hocking Hills in southeastern Ohio, United States. We identified all trees within 0.08-ha plots at 33 nest sites in southwestern Ohio and 30 in Hocking Hills. Red-shouldered Hawks in southwestern Ohio and Hocking Hills used black cherry (Prunus serotina) branches as a nest lining more frequently than expected, based on Bailey's 95% confidence intervals. Black cherry was found in >80% of nests but present in only 57–58% of the vegetation plots, and composed only 4–5% of the trees in the forests of the study areas. White pine (Pinus strobus), red pine (P. resinosa), and eastern hemlock (Tsuga canadensis) also were used more than expected in both study areas. Black cherry is a cyanogenic species and may provide an advantage to nesting Red-shouldered Hawks by functioning as a natural pesticide.
We report a Common Raven (Corvus corax) that learned to turn on a water faucet in a campground at Death Valley National Park, Inyo County, California, USA, and drink from it. Ad libitum availability of water has important implications for survival and reproductive success of desert birds. Ravens commonly exploit anthropogenic sources of water and food; these behaviors are of interest because ravens can be important predators of the federally-threatened desert tortoise (Gopherus agassizii). Our observation is further evidence of the resourcefulness of ravens and challenges involved in limiting access to anthropogenic resources for an intelligent, subsidized predator.
We report observations of a Glossy Flowerpiercer (Diglossa lafresnayii, Thraupidae) using and maintaining sap wells on three shrubs (Asteraceae: Baccharis arbutifolia) on the east slope of the Ecuadorian Andes. The flowerpiercer rotated among shrubs in a trapline fashion, licking and drinking sap and dragging its hooked upper mandible, and possibly also its lower mandible, along the wounds in the Baccharis trunks, presumably to keep sap flowing. This represents, to our knowledge, the first description of sap well use and maintenance in the Thraupidae.