Christopher M. Heckscher

Veery (Catharus fuscescens) Wintering Locations, Migratory Connectivity, and a Revision of Its Winter Range using Geolocator Technology

ABSTRACT. We used light-level archival geolocators to track five Veeries (Catharus fuscescens) for one annual cycle as they migrated from Delaware to South America and back. Southward migration commenced in late August and September 2009. Veeries arrived at wintering sites from 2 November to 2 December 2009. All birds initially wintered in the Amazon basin south of the Amazon River in Mato Grosso, Para, and Amazonas states, Brazil. All birds showed intratropical migration to a second winter site between 7 January and 7 March 2010. These second winter sites were in the interior, northern, and southern periphery of the Amazon basin and the Orinoco River headwaters, Venezuela. Northward migration commenced in mid-April 2010, and the Veeries returned to Delaware between 29 April and 20 May 2010. Despite variation in migratory patterns, several stopover regions were visited by multiple individuals: the coasts of the Carolinas, the coast of the Gulf of Mexico, Cuba and Jamaica, the north coast of Colombia and Venezuela, and southern Venezuela. Our spatial and temporal data necessitates that the Veery winter range include the entire Amazon basin and the headwaters of the Orinoco River, as well as two disjunct regions in Mérida state, Venezuela, and São Paulo state, Brazil. We hypothesize that Veeries initially settled in lowland forest and that intratropical migration was prompted by the ecological factors associated with the seasonal flood pulse of Amazonian rivers. If so, the Veery may be threatened by the recent, unprecedented proposed alteration of Amazonian lowland forests.

Veery Nest Sites in a Mid-Atlantic Piedmont Forest: Vegetative Physiognomy and Use of Alien Shrubs

Abstract Veery (Catharus fuscescens) nest sites were compared to unused sites in a Middle-Atlantic Piedmont forest to determine if nest placement was random or biased with respect to forest structure and alien vegetation. Thus far, available data shows alien plants have a detrimental or neutral effect on the ecology of forest birds; however, empirical data regarding the proximate influence of invasive alien shrubs on avian nest placement in North American forests is lacking. Nest sites were distributed non-randomly in relation to vegetation density and were characterized by dense foliage below 1.5 m with sparse overstory at 2.5 to 3 m. Sites occurred within moist forest in floodplains and on south- and east-facing slopes. All nest sites contained alien shrubs, and alien vegetation supported 84% of nests. Shrub diversity did not differ between nest sites and unused sites yet more alien shrub species were found at nest sites. The density of native shrub-layer foliage did not differ between the two treatments; however, the density of alien shrub foliage was greater at nest sites. In this forest there was no relationship between the density of alien vegetation and the density of native vegetation. These data suggest that alien shrubs have replaced native shrub species and exerted a largely additive effect on foliage density providing the proximate cues for nest placement. The high success rate (70%) of nests within sites used in analyses suggests that the alien shrubs providing these cues are not substantially elevating nest failure rates. Thus, some temperate-breeding Neotropical forest-interior birds may react positively to a change in forest structure resulting from the invasion of alien shrubs. Ecological release resulting from the increase in available nest sites created by alien shrubs may explain the recent regional spread of the Veery. Region-specific studies are needed to determine the forest breeding birds that are affected, either positively or negatively, by the altered spatial heterogeneity created by alien shrubs.

Intratropical migration of a Nearctic-Neotropical migratory songbird ( Catharus fuscescens ) in South America with implications for migration theory

Recent advances in tracking technology have revealed significant intratropical movement of Nearctic– Neotropical migratory songbirds during their non-breeding season. We report the movement of 25 veeries (Catharus fuscescens) over multiple seasons (2009–2013) through equatorial rain forests of South America. Veeries initially settled on the Brazilian Shield geological formation but undertook an intratropical migration to a second South American region in January, February or March. Consequently, our study is the first to track individual forest passerines to document an annual migration from the Brazilian Shield to the Guiana Shield and into lowland regions of Amazonia. The movement and settlement patterns showed no spatiotemporal relationships with Nearctic–Neotropical migration, remained in accordance with the flood pulse of the Amazon basin, and were spatially and temporally complex suggesting relatively ancient ancestral origins. The ability to isolate the migration event from Nearctic–Neotropical migration is an important contribution to the ongoing discourse regarding the evolution of trans-hemispheric migration in the genus Catharus.

Multiple Male Feeders at Nests of the Veery

Abstract We present the first documentation of nestling care by multiple male feeders at nests of the Veery (Catharus fuscescens) in a Mid-Atlantic Piedmont forest in northern Delaware. This is only the second confirmation of this behavior in a Nearctic-neotropical migrant songbird. Five of six nests (83%) were attended by a male that concurrently fed nestlings at a second or third nest. Three of six nests (50%) were attended by one female and two males. No females were observed at more than one nest. We monitored >140 Veery nests at our study site since 1998, and believe the dense breeding habitat and single-brooded nature of the Veery have inhibited our ability to confirm this behavior prior to 2011. Our data suggest this behavior is widespread in our study population.

Rediscovery and Habitat Associations of Photuris Bethaniensis McDermott (Coleoptera: Lampyridae)

Abstract Photuris bethaniensis McDermott, 1953, is recorded only from Sussex County, Delaware, from the original species description. In 1998 we relocated P. bethaniensis near the type locality. From 1998 through 2000, Photuris bethaniensis was found exclusively within freshwater interdunal swales occurring within Delawares backdune depressions. The species was discovered in 7 of 18 swales surveyed within a 25-km stretch of Atlantic shoreline. Photuris bethaniensis was most common in swales with dense shrub thickets. The temporal stability of freshwater interdunal swales may be an important factor influencing the distribution of this species.

FOREST-DEPENDENT BIRDS OF THE GREAT CYPRESS (NORTH POCOMOKE) SWAMP: SPECIES COMPOSITION AND IMPLICATIONS FOR CONSERVATION

Abstract The Great Cypress Swamp Conservation Area (GCSCA) comprises the largest contiguous forest on the Delmarva Peninsula (>5000 ha). An avian inventory using a fifty-meter fixed-radius point count method was undertaken during the nesting seasons of 1996 through 1998 to determine species composition, relative abundance, and frequency of breeding forest birds. Seventy-three species were found to comprise the breeding-season avifauna of this natural area including 14 warblers. Seven of the ten most abundant species were neotropical migrants. The Worm-eating Warbler and the Brown-headed Cowbird were the most abundant and most frequently encountered species, respectively. Several birds of local conservation concern were found, including two regionally rare species: Swainsons Warbler and Black-throated Green Warbler. Two warblers previously known to breed here were not found during this survey: American Redstart and Northern Parula. Management of the GCSCA for forest birds should focus first on protection of extant populations and secondly on restoration. Comprehensive systematic inventories of large areas of contiguous forest should be considered a high priority for biologists concerned with the regional conservation of species of concern.

Veery (Catharus fuscescens) Nest Architecture and the Use of Alien Plant Parts

Abstract The use and potential consequence of alien plant parts in the construction of open-cup leaf nests by Nearctic-breeding forest songbirds has not been investigated. We dissected 19 leaf nests constructed by Veeries (Catharus fuscescens) over two breeding seasons in a temperate broadleaf forest infested with alien plants. Our objectives were: (1) confirm the architectural approach used by Veeries to construct nests, (2) determine if Veeries used alien plant parts in nest construction, (3) determine if nest success was related to the use of alien material, (4) determine the use of alien plants relative to native plants, and (5) test for an association of alien plant mass with the progression of the nesting season. Our results showed that Veeries constructed three separate nest layers: (1) a platform for support, (2) an inner cup, and (3) nest lining. Veeries incorporated parts from six alien plant species in their nests representing 22% of the 27 species used. All nests contained alien plant parts but use differed among the three layers. In particular the use of stems of Alliaria petiolata and Rosa multiflora, two alien species, appeared to provide important structural support in the nests outer layers. Although our sample size was small, we found no relationship between the use of alien plant parts and nest failure suggesting use of alien plant material does not have negative effects on productivity. We caution that sudden large-scale restoration efforts, which remove the alien forest plant species used in nest construction prior to the recovery of comparable native species, may result in the temporary reduction of materials available to birds for nest construction.

Delaware Photuris Fireflies (Coleoptera: Lampyridae): New State Records, Conservation Status, and Habitat Associations

ABSTRACT: In the Middle-Atlantic region, the distribution, abundance, and habitat associations of fireflies in the genus Photuris are poorly understood. Six species in Photuris are recorded from Delaware. Ten years (1998–2008) of periodic survey work has yielded three new state records and contributed valuable information regarding species abundance and habitat affiliations in this region. Results from that survey are summarized and compared to previously published Delaware records. This is the first concerted effort to report the conservation status and the associated habitat and natural community types of Photuris fireflies from the Middle-Atlantic region.

The Seasonal Pattern of Veery Calls and Song in Relation to Reproductive Contexts

Abstract I investigated the seasonal patterns in the use of Veery vocalizations (song and calls) at a breeding site in northern Delaware. The Veery call repertoire consists of 2 continua (harsh and tonal notes) and 4 discrete call types. Veeries use these calls in long-distance (inter-territory) and short-distance (intra-territory) vocal interaction. To gain insight to Veery communication, I tallied calls during twenty-six 10-min point-counts in seven 11-d periods to determine the pattern of call types used by Veeries from nest initiation through fledging. The pattern of calls used varied depending on the corresponding reproductive context and can be in part explained by their acoustic properties in varying social situations. The use of a variety of calls early in the breeding season coupled with a paucity of song confirms that calls are the primary acoustic signal used by Veeries during the first 2 weeks after spring arrival.

Reproductive outcomes determine the timing of arrival and settlement of a single-brooded Nearctic–Neotropical migrant songbird (Catharus fuscescens) in South America

ABSTRACT The breeding seasons of Nearctic–Neotropical migratory songbirds are thought to be constrained by the temporal demands of subsequent seasons. In any population, a subset of adults may fail to fledge young despite repeated attempts, which may prolong reproductive effort. We used geolocators to track the single-brooded Veery (Catharus fuscescens) from a Delaware, USA, breeding site to South America and back, to examine how reproductive failure and the timing of reproduction affected the spatiotemporal aspects of the nonbreeding season. We also considered the effect of additional variables: age, sex, time in population (i.e. experience), productivity, and nutrition via ptilochronology. We found that clutch completion date and reproductive success were significant predictors of South American entry and arrival date at first winter sites, respectively. Reproductive success also influenced the latitude of winter sites. For females only, there was a consequence of reproductive failure: unsuccessful females entered South America later, and arrived at first winter sites later, than successful females. Although there was a trend for unsuccessful females to exit South America earlier the following spring, they did not arrive in Delaware earlier, nor were they more reproductively successful the following year. We found an effect of age and sex on the timing of South American exit. Females differed from males in the timing of fall migration in South America, the timing of South American exit, and the timing of arrival back in Delaware. Our finding that arrival and settlement of adult Veeries in South America is primarily determined by former reproductive outcomes, rather than age, sex, or life history experience, is consistent with the contention that the breeding season of single-brooded species is constrained by subsequent seasons. Our results have implications for conservation, considering that the effect of reproductive failure goes beyond reduced fecundity.