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We sequenced 912 bp of the cytochrome-b gene to examine phylogenetic relationships of the enigmatic Saw-billed Hermit (Ramphodon naevius), a large and distinctive hummingbird endemic to tropical forests of southeastern Brazil. Bootstrapped maximum parsimony and maximum likelihood analyses of sequence data from 11 hummingbirds and several outgroups (two swifts, one goatsucker) support: (a) monophyly of the traditional hermit (Phaethornithinae) and nonhermit (Trochilinae) subfamilies, (b) placement of Ramphodon among hermits, and (c) a sister relationship between Ramphodon and an exemplar of the widespread polytypic hermit genus Glaucis. The association of Ramphodon with derived hermit lineages is concordant with subfamilial patterns of wing anatomy and nest architecture. However, the unusual plumages (striped underparts) and male bills (long, serrated, hooked) shared by Ramphodon and the Tooth-billed Hummingbird (Androdon aequatorialis) appear to have evolved within separate hermit and nonhermit “tooth-billed” clades. Distal placement of the Ramphodon-Glaucis clade within hermits implies that even distinctive Brazilian endemics such as Ramphodon are derived forms that evolved relatively recently.
Here we describe the first nesting records of the Moustached Antpitta (Grallaria alleni). We found two nests in sub-Andean forests in the Central Andes of Colombia at 1,800 m and in northwestern Ecuador at 1,900 m elevation during November 1995 and March 1999. Both nests were bulky structures with an open deep cup, made with moist plant material, including damp dead leaves, fresh mosses, rootlets, and small stems and fibers. The eggs were aquamarine and the nestlings were covered by dark gray down and had vermilion bills and gapes. Nests of G. alleni are similar to the nests of the closely related G. guatimalensis in construction and dimensions. This note contributes new information on this endangered and poorly known species.
We describe the nest site characteristics, and report on the association between site characteristics and reproductive success (brood size at day 8), for a population of American Robins (Turdus migratorius) breeding in the Toiyabe Mountains of central Nevada. Based on data from 132 nests, the immediate vicinity (a 10-m radius) around robin nests was sparsely vegetated with limited cover at any vegetation height. Nest tree diameters at breast height were not significantly different from those of nearby trees. Based on tree availability in the immediate vicinity, robins chose to nest in single-leaf pinyon (Pinus monophylla) more often (49.6% of nests used versus 39.3% availability), and quaking aspen (Populus tremuloides) less often (24.8% of nests used versus 52.1% availability), than expected by chance. Contrary to predictions based on previous studies, there was no change from coniferous to deciduous trees for nesting as the breeding season progressed, nor did robins build their nests higher in trees later in the season. Nest orientation was significantly directional in the 90° arc between east and south, but was unrelated to the amount of concealment conferred by shrub and bush cover in the four quadrants around the nest. Solar insolation resulting from nest placement was not related to brood size at day 8 and there were no discernable relationships between either solar insolation or orientation and clutch initiation date. Brood size on day 8 was inversely related to mean dbh of the surrounding trees, while canopy cover and height were associated positively with larger broods at day 8.
We studied populations of Song Sparrows (Melospiza melodia) on 11 islands near Victoria, British Columbia, to evaluate the relationship between nest site characteristics and parasitism by Brown-headed Cowbirds (Molothrus ater). For all nests we recorded their height, the height of vegetation above the nest, the percentage of overhead and side exposure, the number of perches in trees and shrubs within 10 m of the nest, and the distance to the nearest tree or shrub perch. Song Sparrow nests within 10 m of trees were parasitized more often than those farther from trees. Estimates of overhead and side exposure also were lower for parasitized nests than unparasitized nests. Our results support the hypotheses that the proximity of trees, and the amount of concealing cover around host nests, influence the success of cowbirds searching for nests to parasitize.
We studied the nesting ecology of Winter Wrens (Troglodytes troglodytes) from 1994–1996 in coastal, coniferous, temperate rain forest of southeastern Alaska. Overall nesting success (estimated by the Mayfield method) of 143 nests exceeded that reported for other published studies of temperate wrens, including T. troglodytes. Wrens used understory nest sites (logs, stumps, root disks of uprooted trees, understory moss, stream banks) in two forest sites where predation of nests was low (2% of 65 nests). Males at these two sites commonly had small territories (1.8 ha ± 0.3 SE and 1.2 ha ± 0.1 SE) and often mated polygynously (22% and 78% of males had at least two mates). In the third study area, where predation (probably by red squirrels, Tamiasciurus hudsonicus) on understory nests was relatively high (19% of 59 nests), nests most often were placed in moss clumps on tree branches, as high as 18 m above ground. Males in this study area had the largest territories (2.8 ha ± 0.4 SE) and most (90%) mated monogamously. Variation in nesting ecology among these three superficially similar (mature conifer forest) sites may be related to subtle differences in habitat features and predator abundance.
We examined the distribution and abundance of the Coastal Plain Swamp Sparrow (Melospiza georgiana nigrescens) at previously occupied sites and points within potential habitat. We found Swamp Sparrows throughout their formerly documented range except in southern Chesapeake Bay. Swamp Sparrows were most common in the Mullica River region of New Jersey where we detected individuals at 78% of systematically chosen points with a mean count of 4.1 birds/point. The percentages of points with positive detections in the regions of Delaware River (39%), eastern Delaware Bay (23%), western Delaware Bay (34%), and Tuckahoe River (31%) were lower. The mean count of birds/point was between 0.4 and 0.6 in these regions. A higher resolution Poisson model of relative abundance suggested that the greatest concentrations of Swamp Sparrows occurred not only in the Mullica River area but also along northwestern Delaware Bay. Regression analysis of Swamp Sparrow counts and habitat features identified shrubs (Iva frutescens and Baccharis halimifolia) as a key habitat component. By applying density estimates generated by DISTANCE (Thomas et al. 1998) to the approximate area of potential shrub habitat along Delaware Bay, we estimated that the core population of Coastal Plain Swamp Sparrows was less than 28,000 pairs. We recommend that the Coastal Plain Swamp Sparrow be listed as a subspecies of concern by state and local governments because of its relatively small population size, restricted distribution in the mid-Atlantic region, and narrow habitat requirements.
The Plain Pigeon (Columba inornata) was listed as endangered in Puerto Rico in 1970. During 1986–1992 and 1997–2001, we collected point transect survey data to estimate density, population size, and rate of change. Density and population size estimates increased between 1986–1992 and 1997–2001. With a mean density of 0.25 ± 0.06 SE individuals/ha and a mean population size in the area of the surveys of 3,746 ± 892 SE individuals during 1997–2001, we believe that the status of the Plain Pigeon is not as precarious as it was during 1986–1992, when mean density was 0.02 ± 0.003 SE individuals/ha and mean population size in the area of the surveys was 218 ± 42 SE individuals. However, Plain Pigeons are not widely distributed and the loss and fragmentation of second growth forests combined with the effects of hurricanes and other factors may cause their extinction. Because Plain Pigeons have a spatially clumped distribution, we recommend sampling at least 1,195 points during peak nesting activity (March through June) throughout the island, with at least 526 points covering areas of abundance in eastcentral Puerto Rico, to monitor population changes and evaluate the effectiveness of management actions.
Previous authors have noted the unique singing behavior and apparently large song repertoires of male Yellow-breasted Chats (Icteria virens). We studied the singing behavior of 10 male chats in central Kentucky in an attempt to determine the size and functions of their song type repertoires and examine possible relationships among singing behavior, morphological characteristics, and reproductive success. During the 1995 breeding season, we recorded and analyzed chat songs and determined the morphological characteristics and reproductive success of focal males. Repertoire sizes varied among male chats, ranging from 46–81 song types. Larger males (as determined by tarsus length) had larger song type repertoires, and males with longer wing chords fledged more young. These relationships suggest a correlation between male quality (as determined by size and reproductive success) and repertoire size. Male chats spent less time singing after pairing, suggesting that singing plays a role in mate attraction. However, singing by male chats likely serves other functions, such as territorial defense and attracting additional mates, because males continued singing after pairing. In contrast to male wood-warblers (Parulidae), male chats have relatively large repertoires of song types and also vary the sequence of song types, the frequency of repetition of individual song types, and the length of time between consecutive song types. Such differences in singing behavior lend support to the hypothesis that chats are not parulids.
Female Magellanic Penguins (Spheniscus magellanicus) fought for the best quality nests, mainly before egg laying. Female fights (n = 47) were longer than male fights (n = 138), but less frequent and less intense as indicated by the number of flipper hits and length of cuts. Female winners occupied the disputed nests, and losers usually moved to nests of lower quality. Losers subsequently fledged fewer chicks than winners. Female winners were in better body condition, were not significantly larger, and were the owners of the nest as indicated by previous season attendance at the nest.
Although Common Yellowthroats (Geothlypis trichas) are Nearctic-Neotropical migrants that are common breeders across the United States and Canada, very little has been published about the migration and stopover ecology of this species. We used spring migration banding records of Common Yellowthroats from 1992–2001 on Appledore Island, Maine, to investigate potential sexual and age-related differences in migration timing and stopover ecology of this species. Arrival dates of males were significantly earlier than arrival dates of females during spring, with mean male arrival five days earlier than female arrival. Also, after-second-year (ASY) birds arrived significantly earlier than second-year (SY) birds within each sex. Males also were significantly heavier than females upon arrival on Appledore. During spring migration, 5.0% of males and 4.2% of females were recaptured at least one day after initial capture, resulting in a mean stopover length of approximately three days for both sexes. We found no significant difference in the mean minimum stopover length nor the rate of mass change between the sexes based on recaptured individuals. Furthermore, we found no significant differences in stopover ecology between age groups within either sex. Both sexes significantly increased mass during stopover, both as calculated from recaptured individuals and as estimated by regression of condition (mass × 100/wing chord) over time. Results of this study confirmed differential migration among Common Yellowthroats, which is consistent with previous studies of passerine migration ecology. Lack of differences in stopover ecology between the sexes or between age groups suggests that earlier arrival of males than females and of ASY birds than SY birds may be due to an earlier onset of migration rather than increased migration speed.
We describe a nest of the Silvery-fronted Tapaculo (Scytalopus argentifrons), a member of a large genus in which only one-fourth of the species have described nests. The nest, found in a Costa Rican cloud forest and containing two chicks, was a substantial globular structure constructed mostly of moss, located in a subterranean cavity at the end of a short, narrow tunnel.
Here I report the first case of double brooding in a Swainson's Warbler (Limnothlypis swainsonii). On 7 June 2002, I observed a color-banded female feeding an 8-day-old fledgling 20 m from her first nest. On 12 July 2002, I saw the same bird feeding a banded 12-day-old fledgling 8 m from her second nest. Double brooding is one strategy by which a genotype may increase genetic representation in future generations.
We report on the use of a Northern Cardinal (Cardinalis cardinalis) nest by fledgling Carolina Wrens (Thryothorus ludovicianus) during a period of inclement weather. We found four fledgling wrens in a newly lined cardinal nest on the morning of 22 May 2002 during a heavy frost. The use of the cardinal nest by the wrens may have been precipitated by the unexpected frost. This represents a unique method of protection from inclement weather taken by young birds.
On 11 April 2002, in San Pedro, Belize, we observed a male Golden-fronted Woodpecker (Melanerpes aurifrons dubius) cache a mouse carcass and subsequently provision nestlings with tissue taken from it. During 12 min of observation, the male made seven trips with pieces of the carcass, taking pieces of muscle to the nestlings and consuming skin and connective tissue himself. This is the first published record of the consumption of mammalian prey by this species.
The natural incubation period of Great Frigatebird (Fregata minor) eggs reported in the literature (55 days) was 74% longer than the value predicted from initial egg mass (89.1 g). The long incubation period was associated with a low daily water loss (213.5 mg/day) from the eggs and few pores in the eggshell (4,643 pores/egg). The initial event in the pipping process, which represented 7.2% of the duration of the incubation period but accounted for 24.9% of the total water loss from the egg, was a star-shaped fracture of the shell which increased water loss from the egg and persisted for several days before hatching was complete. These characteristics of the eggs of the Great Frigatebird are contrasted with those from the Red-footed Booby (Sula sula), the only other altricial, pelecaniform seabird with a long incubation period, for which data are available.
We observed a male Prothonotary Warbler (Protonotaria citrea) eating a 3-cm lizard in Louisiana. There are few reports in the literature of wood warblers taking vertebrate prey, and we found no other record for a Prothonotary Warbler doing so.
An adult Harpy Eagle (Harpia harpyja) attacked and killed an infant collared peccary (Pecari tajacu) at a site in eastern Amazonia. The eagle appeared to have been prevented from removing its prey immediately by surviving members of the peccary herd. Circumstantial evidence suggests that a set of specific factors, including the abundance of peccaries at the site and forest structure, may have facilitated the attack.
This paper presents an updated account of 34 wading bird foraging behaviors presented by Kushlan (1978a) with findings from later studies for nine wading bird species, including: Great Egret (Ardea alba), Snowy Egret (Egretta thula), Little Blue Heron (Egretta caerulea), Tricolored Heron (Egretta tricolor), Great Blue Heron (Ardea herodias), Green Heron (Butorides virescens), Glossy Ibis (Plegadis falcinellus), White Ibis (Eudocimus albus), and Wood Stork (Mycteria americana). We also include occurrences of the behavior Prey Dropping, which was not described as a foraging behavior in Kushlan (1978a).