PO Box 153

Califon, NJ, United States

PO Box 153

Califon, NJ, United States
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Trierweiler C.,University of Groningen | Trierweiler C.,Institute of Avian Research Vogelwarte Helgoland | Trierweiler C.,Dutch Montagus Harrier Foundation | Mullie W.C.,Project Biological Management of Locusts and Grasshoppers | And 7 more authors.
Journal of Animal Ecology | Year: 2013

Mid-winter movements of up to several hundreds of kilometres are typical for many migratory bird species wintering in Africa. Unpredictable temporary food concentrations are thought to result in random movements of such birds, whereas resightings and recoveries of marked birds suggest some degree of site fidelity. Only detailed (e.g. satellite) tracking of individual migrants can reveal the relative importance and the causes of site choice flexibility and fidelity. The present study investigates how mid-winter movements of a Palaearctic-African migratory raptor, Montagu's harrier Circus pygargus, in the Sahel of West Africa are related to the availability of food resources. Thirty harriers breeding or hatched in northern Europe were satellite tracked (2005-2009). On average, four home ranges, each separated by c. 200 km, were visited during one overwinter stay in the Sahel. Wintering home ranges were similar in size to breeding season home ranges (average over wintering and breeding home range size c. 200 km2), and harriers showed high site fidelity between years. Most preferred habitat types in the Sahel were mosaics of grass- and cropland, indicating similar habitat preferences in both the breeding- and wintering seasons. The main prey of Montagu's harriers in the Sahel were grasshoppers Acrididae. Highest grasshopper numbers in the field occurred at relatively low vegetation greenness [normalized difference vegetation index (NDVI) values 0·17-0·27]. We used NDVI as a proxy of food availability for harriers. During their overwinter stay, Montagu's harriers moved in a South-South-western direction between consecutive home ranges. The birds selected areas within the range of NDVI values associated with high grasshopper numbers, thus tracking a 'green belt' of predictable changes in highest grasshopper availability. Contrary to earlier hypotheses of random movements in the Sahelian-wintering quarters, the present study shows that Montagu's harriers visited distinct home ranges, they were site-faithful and tracked seasonal changes in food availability related to previous rainfall patterns, caused by the shifting Intertropical Convergence Zone. Itinerancy may be the rule rather than an exception among insectivorous birds wintering in African savannahs. © 2012 The Authors. Journal of Animal Ecology © 2012 British Ecological Society.


Vinyard C.J.,Northeast Ohio Medical University | Glander K.E.,Duke University | Teaford M.F.,High Point University | Thompson C.L.,Northeast Ohio Medical University | And 2 more authors.
International Journal of Primatology | Year: 2012

We lack a general understanding of how primates perform physiologically during feeding to cope with the challenges of their natural environments. We here discuss several methods for studying the ecological physiology of feeding in mantled howlers (Alouatta palliata) at La Pacifica, Costa Rica. Our initial physiological effort focuses on recording electromyographic activity (EMG) from the jaw muscles in free-ranging howlers while they feed in their natural forest habitat. We integrate these EMG data with measurements of food material properties, dental wear rates, as well as spatial analyses of resource use and food distribution. Future work will focus on incorporating physiological measures of bone deformation, i. e., bone strain; temperatures; food nutritional data; and hormonal analyses. Collectively, these efforts will help us to better understand the challenges that howlers face in their environment and the physiological mechanisms they employ during feeding. Our initial efforts provide a proof of concept demonstrating the methodological feasibility of studying the physiology of feeding in free-ranging primates. Although howlers offer certain advantages to in vivo field research, many of the approaches described here can be applied to other primates in natural habitats. By collecting physiological data simultaneously with ecological and behavioral data, we will promote a more synthetic understanding of primate feeding and its evolutionary history. © 2012 Springer Science+Business Media, LLC.


Heinrich B.,PO Box 153
Northeastern Naturalist | Year: 2015

Iris pseudacorus (Yellow Flag Iris), normally produces 1 flower, or exceptionally, it can produce more than 1 flower per stalk at any one time. Flower buds and opened flowers are available at all times every day, but the transition stages between buds and expanded flowers are not. I here report that the flowers open explosively and discuss the proximate cause and the potential significance of this behavior.


Heinrich B.,PO Box 153
Northeastern Naturalist | Year: 2015

I observed 12 nesting cycles of Tachycineta bicolor (Tree Swallow) with emphasis on the choice of nest materials used, timing of egg-laying, presence and behavior of conspecifics, and nesting success. All Tree Swallows built nests of dried grasses predominantly lined with large, plumed white feathers, but nest-lining behavior did not occur until after egg-laying began. When I experimentally removed feather-linings from one nest, the pair replaced them. In all nests, the birds tucked the feather quills under the eggs with the plumes arching over them. The Tree Swallows showed a strong preference both for shape of feathers and their color contrast from background. The Tree Swallows exhibited vigorous territorial behavior and nest-guarding from conspecifics before nest-building started, continued until early incubation, and then ceased when the young hatched. Birds other than the nest owners were frequent visitors in the nest area and they sometimes entered nests throughout the nesting cycle. Indirect evidence suggests that extra-pair eggs appearing in the nest and "extra" young accounted for nestling mortality . I here infer that although Tree Swallows experience strong nest parasitism, feather-lining behavior hides information on nest contents and thus reduces parasitism. © 2015, BioOne. All rights reserved.


Heinrich B.,PO Box 153
Northeastern Naturalist | Year: 2016

Scolopax minor (American Woodcock) is well-known for its crepuscular foraging, nuptial sky dance, and concealment by both cryptic coloration and immobility. It occasionally engages in a highly conspicuous rocking motion that has been interpreted by some as a strategy for worm-hunting. However, the literature on this behavior, combined with current observations and theory, can instead more plausibly be interpreted as an advertisement of unprofitability.


Heinrich B.,PO Box 153
Northeastern Naturalist | Year: 2014

Wild stock Castanea dentate (American Chestnut) were planted at the edge of a forest clearing in western Maine in 1982, and four had grown to a height of 13 m and diameter breast high of 39 cm by 2014. They showed no sign of disease and were producing annual seed crops. The seeds had been spread in the surrounding forest by animal-made seed caches placed up to at least 300 m from the source; 238 surviving offspring (119 of them one-year old) of the planted trees were located in 139 groupings. Of the surviving seedlings, 110 were growing singly, although groupings ranged from two to 20. At least six of the animal-spread seeds had, by 2014, produced 2-6.5-m-tall saplings that were growing up to 70 cm per year. Experiments of seed survival showed high seed predation at or near the ground surface, but fresh seeds placed 10 cm underground in the fall had 80% survival to the seedling stage after one year. Comparative behavior of seed foragers, as well as the distance and pattern of seed dispersal, implicate Cyanocitta cristata (Blue Jay) as the most likely primary dispersers and planters of the chestnut seeds. © 2014, Northeastern Naturalist.

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