Eagle Nests Research Articles

Monitoring bald eagles using lists of nests: Response to Watts and Duerr

AbstractThe post‐delisting monitoring plan for bald eagles (Haliaeetus leucocephalus) roposed use of a dual‐frame sample design, in which sampling of known nest sites in combination with additional area‐based sampling is used to estimate total number of nesting bald eagle pairs. Watts and Duerr (2010) used data from repeated observations of bald eagle nests in Virginia, USA to estimate a nest turnover rate and used this rate to simulate decline in number of occupied nests in list nests over time. Results of Watts and Duerr suggest that, given the rates of loss of nests from the list of known nest sites in Virginia, the list information will be of little value to sampling unless lists are constantly updated. Those authors criticize the plan for not placing sufficient emphasis on updating and maintaining lists of bald eagle nests. Watts and Duerr's metric of turnover rate does not distinguish detectability or temporary nonuse of nests from permanent loss of nests and likely overestimates turnover rate. We describe a multi‐state capture–recapture model that allows appropriate estimation of rates of loss of nests, and we use the model to estimate rates of loss from a sample of nests from Maine, USA. The post‐delisting monitoring plan addresses the need to maintain and update the lists of nests, and we show that dual frame sampling is an effective approach for sampling nesting bald eagle populations. © 2011 The Wildlife Society.

Cave, City, and Eagle's Nest: An Interpretive Journey through the Mapa de Cuauhtinchan No. 2. By Davíd Carrasco and Scott Sessions, eds.

Cave, City, and Eagle's Nest: An Interpretive Journey through the Mapa de Cuauhtinchan No. 2. By Davíd Carrasco and Scott Sessions, eds.

Bald Eagle Predation of a White-Tailed Deer Fawn

Abstract Haliaeetus leucocephalus (Bald Eagle) is an adaptable predatory bird that commonly captures live prey, but regularly scavenges. Large mammalian prey (e.g., Odocoileus virginianus [White-tailed Deer]) have been observed in Bald Eagle diets, but were considered scavenged. To our knowledge, Bald Eagle predation of a live ungulate has only been reported once, and occurred in Menominee County, MI. In June 2009, we captured and radiocollared a female White-tailed Deer fawn (2.7 kg) in the south-central Upper Peninsula of Michigan. The fawn was last radiolocated alive 8 h after release in a short-height (20–30 cm) grassland field along a river approximately 570 m from an eagle nest. Estimated time of mortality of the fawn was 10 h post release. Approximately 27 h post release, 2 legs, >50% fawn hide, and the radiocollar were present in the nest along with 2 eagle nestlings (estimated age 9–10 wks). We believe this was a possible predation event based on the 8-h period between fawn relocations, fawn move...

Adoptions of Young Common Buzzards in White-tailed Sea Eagle Nests

Documentation of interspecific adoption of young is rare in the published literature among birds. We survey six cases of young Common Buzzards (Buteo buteo) adopted in nests of White-tailed Sea Eagle (Haliaeetus albicilla) in central Europe (Czech Republic and Hungary). Common Buzzard nestlings adopted were in good condition and adult White-tailed Sea Eagles fed and cared for them properly. Young Common Buzzards successfully fledged and left the White-tailed Sea Eagle nests. The most probable explanation of this phenomenon is a non-lethal predation of Common Buzzards followed by White-tailed Sea Eagle parental care as a result of parental recognition error. Similar cases of adoption of Red-tailed Hawk (Buteo jamaicensis) nestlings in nests of Bald Eagle (Haliaeetus leucocephalus) have been documented in North America.

An Adaptive-Management Framework for Optimal Control of Hiking Near Golden Eagle Nests in Denali National Park

Unintended effects of recreational activities in protected areas are of growing concern. We used an adaptive-management framework to develop guidelines for optimally managing hiking activities to maintain desired levels of territory occupancy and reproductive success of Golden Eagles (Aquila chrysaetos) in Denali National Park (Alaska, U.S.A.). The management decision was to restrict human access (hikers) to particular nesting territories to reduce disturbance. The management objective was to minimize restrictions on hikers while maintaining reproductive performance of eagles above some specified level. We based our decision analysis on predictive models of site occupancy of eagles developed using a combination of expert opinion and data collected from 93 eagle territories over 20 years. The best predictive model showed that restricting human access to eagle territories had little effect on occupancy dynamics. However, when considering important sources of uncertainty in the models, including environmental stochasticity, imperfect detection of hares on which eagles prey, and model uncertainty, restricting access of territories to hikers improved eagle reproduction substantially. An adaptive management framework such as ours may help reduce uncertainty of the effects of hiking activities on Golden Eagles.

In the Beginning Was the Image, before the Beginning Was the Avant-Garde ...

By virtue of its position-avant, in a montage of texts- should the preface not aspire to be an artifice worthy of being dubbed avant- garde (by the voice of the reader)? threat rather than an invitation, an attempt to soften up an entrenched enemy, a plan for the murder of the watchmen-avant- garde, garder, regarder ... where to begin? PREFACE: Preface for a Proposal for an Avant- Garde film. Title: A GIRL, a TREE, the FALL. Titles: Handwritten (not in copperplate style), white on black. Dedication: To Jean- Lucifer Godard and Guillaume Apollinaire. Epigraph: Handwritten in smudged crimson blood- spattered red ink over black- and- white still from the film Le Petit Soldat: Il faut imaginer les victimes heureuse [It is necessary to imagine the victims happy]. Sound track over titles: Blonde ... by Guesh Patti. Image 1 The liminal of the forest, a huge pine tree, reverse- silhouetted in light, towering above the canopy, the edge of darkness below. mythic image. Posed on the threshold between order and adventure. On a crucifix of bleached tree boughs, one painted in lush gold leaf, rests an ea gle's nest; as neatly woven as a Pathan girl's veil. male voice intones: Is this the tree of life, or tree of death? Music: Electronic Wind, from the sound track of the film Fire in the Water. Image 2 lovely young girl, long blond hair (Rus sian peasant style), in jeans and arctic coat, with climbing spikes on her boots and a rope around her waist and the tree, starts her climb from the base of the tree ... dissolve ... she arrives at the huge nest. Taking out a multicoloured rope from her rucksack, she ties it to the golden bough and flings it into space, where it falls uncoiling in slow motion like a molecule of DNA, creating life. Music: Pink Floyd, Shine on You Crazy Diamond, from Wish You Were Here. Image 3 Several pairs of hands tying planks of wood, steel hammers, bags of nails, ropes, buckets, cartons of food, plastic containers of water; fastening them to the rope before it is hauled above by the girl. Music: Miles Davis, Ascenseur pour l' echafaud. Image 4 white- headed ea gle circling in the sky above the nest. Music: Stockhausen, Light. Image 5 panoramic view from the nest. The margin of the arctic, the once treeclad tundra now an industrial wasteland; scattered as far as the eye can see [with] the splintered remains of a million felled trees. Huts. Machines. Diggers. TV news cameramen. Music: Sibelius: Finlandia. Image 6 The tree house is complete. Under her makeshift roof, the girl sleeps. At peace with herself. Music: Kraftwerk: Trans- Europe Express. Images 7- 70 (As we can easily imagine the rest of the REAL, unfolding narrative, we do not need to see it.) Instead we imagine with the girl; we enter into and witness her dreams of how it might have been if she had full control of the images created of this consummate per for mance of hers, living in her nest for three months or so- the film she would have made of the joy she had known in life and nature, and the misery now, of the death of the tree of life. Over this long montage of sensual images, a desolate sound track: a man's voice describing the impossibility of making a film that will change anything. That time cannot be reversed. The tree once cut down, has gone. Avant or apres ... we live and die on the pivot word: Time. Music: Verdi's Requiem. Image 7 The body of the girl lying on the ground next to the bole [trunk] of the tree, where she has fallen. Slow pan toward the machine that will cut down the tree, next to the ambulance, blue light circling. Music: Pink Floyd, Dark Side of the Moon. Image 8 The ea gle circling in the sky above the canopy of the few remaining trees of the ancient forest. …

Hatching Synchrony, Green Branch Collecting, and Prey Use by Nesting Harpy Eagles (Harpia harpyja)

Abstract We observed an occupied Harpy Eagle (Harpia harpyja) nest over three separate periods in eastern Venezuela. Both eggs in the clutch hatched on the same day, and two nestlings competed in the nest for 14 days before one succumbed. The female adult collected green branches 45 times over 60 days of observation. Green branch deliveries were positively associated with prey deliveries and our observations best support the ‘nest sanitation by covering prey’ hypothesis for the adaptive significance of green branch collecting. Prey delivery rate to the nest averaged one delivery every 2.4, 2.1, and 3.7 days in the three observation periods. Three-toed sloths (Bradypus tridactylus) and wedge-capped capuchins (Cebus olivaceus) were the most common prey items brought to the nest.

Local and Landscape Habitat Selection of Nesting Bald Eagles in East Texas

Throughout their range, Haliaeetus leucocephalus (Bald Eagle) have experienced dramatic population increases, and breeding productivity has returned to levels observed prior to the impacts of DDT. To effectively manage growing Bald Eagle populations, habitat and anthropogenic characteristics influencing nest-site selection need to be quantified at multiple spatial scales. In this study, we examined local and landscape characteristics and anthropogenic features influencing nest-site selection by Bald Eagles in 3 National Forests in east Texas. On a local scale, Bald Eagles placed nests in large super-canopy coniferous trees, with nest sites surrounded by shorter and smaller trees than random sites. Bald Eagle nest sites were best predicted by basal area on a local level and distance to nearest human habitation on a landscape level, as determined by logistic regression. We suggest that conservation efforts for Bald Eagles in east Texas should include allowing forests to mature and reducing disturbance around large water bodies to conserve and create suitable nesting habitat on public and private lands.

Comparative nest habitat characteristics of sympatric White‐tailed Haliaeetus albicilla and Golden Eagles Aquila chrysaetos in western Scotland

Capsule Golden and White‐tailed Eagles selected different habitats for nesting. Aim To investigate differences in nesting habitat used by sympatrically breeding eagles in western Scotland, following reintroduction of White‐tailed Eagles from 1975 onwards. Methods Nest‐site locations from national surveys in 2003–05 were entered into a geographical information system (GIS) in order to measure a set of geographic parameters for each nest site. Binary logistic regression with backwards deletion of non‐significant terms was used to derive minimum adequate models at two spatial scales of the likelihood of an eagle nest belonging to one species or the other. We compared changes in occupancy between 1992 and 2003 of Golden Eagle territories inside and outside a GIS model of potential White‐tailed Eagle habitat and according to proximity to White‐tailed Eagle nests. Results White‐tailed Eagles nested at lower altitudes than Golden Eagles, in more wooded habitats with more open water close by, tending to nest in trees where these were present. There were 3359 km2 of potential White‐tailed Eagle nesting habitat within 25 km of existing White‐tailed Eagle nests, containing 54 Golden Eagle territory centres, but we found no difference in change of occupancy for Golden Eagle territories close to White‐tailed Eagles compared with those further away. Conclusion White‐tailed and Golden Eagles appear to partition nesting habitat in the west of Scotland by altitude. This corresponds with behaviour in western Norway and with the situation described in historical accounts of nest‐sites in western Scotland prior to extinction of White‐tailed Eagles. It is also consistent with recent studies showing little overlap in breeding season diet of Golden and White‐tailed Eagles in western Scotland, and likely partitioning of foraging habitat by altitude. We conclude that the likelihood of competitive exclusion is less than previously suggested.

Mycobacterium arupense among the isolates of non-tuberculous mycobacteria from human, animal and environmental samples

Mycobacterium arupense is a non-tuberculous, potentially pathogenic species rarely isolated from humans. The aim of the study was to ascertain the spectrum of non-tuberculous mycobacteria within 271 sequenced mycobacterial isolates not belonging to M. tuberculosis and M. avium complexes. Isolates were collected between 2004 and 2009 in the Czech Republic and were examined within the framework of ecological studies carried out in animal populations infected with mycobacteria. A total of thirty-three mycobacterial species were identified. This report describes the isolation of M. arupense from the sputum of three human patients and seven different animal and environmental samples collected in the last six years in the Czech Republic: one isolate from leftover refrigerated organic dog food, two isolates from urine and clay collected from an okapi (Okapia johnstoni) and antelope bongo (Tragelaphus eurycerus) enclosure in a zoological garden, one isolate from the soil in an eagle's nest (Haliaeetus albicilla) band two isolates from two common vole (Microtus arvalis) livers from one cattle farm. All isolates were identified by biochemical tests, morphology and 16S rDNA sequencing. Also, retrospective screening for M. arupense occurrence within the collected isolates is presented.

Factors Affecting Habitat Selection by Breeding Lesser Spotted EaglesAquila pomarinain Northeastern Poland

We tested a hypothesis on the influence of prey distribution on habitat selection by the Lesser Spotted Eagle Aquila pomarina in north-eastern Poland during the breeding season. We analysed the habitat composition in schematic territories around the nests of 116 breeding pairs of eagles (in a radius of 3 km) and related them to randomly selected sites. Next, we compared the habitat requirements of potential prey species with the proportion of different prey categories found in the eagle's diet. We demonstrated that, in contrast to random sites, eagle nests were located closer to the forest edges. The habitat composition of schematic territories of eagles was different from the random sites owing to the lower proportion of forest and higher proportion of meadows and agricultural land. The feeding habits of Lesser Spotted Eagles were opportunistic, and the diet was composed mainly of rodents (voles), insectivorous mammals (hedgehogs and moles), small birds, and amphibians. Small prey species (body mass below 50 g) and species indicating preferences for open habitats dominated in the diet of eagles (69% and 74% of prey captured respectively). Prey species inhabiting grasslands were hunted more frequently than species preferring agricultural areas. Moreover, eagle pairs nesting deep in the forest interior captured relatively more larger-sized species, whereas the proportion of small prey in the eagle's diet increased as the distance of nest from forest edge decreased. We hypothesize that eagles have to breed closer to the forest edge to minimize energy expenditure and time associated with prey capture and delivery to the nest.

Rescued from an eBay site

A poster for W.H. Power's touring production of The Ivy Leaf , an American melodrama celebrating life in rural Ireland, suggests a reliable source for Edison's 1908 film Rescued from an Eagle's Nest . Challenging Charles Musser's claim that this film, produced by Edwin S. Porter, directed by J. Searle Dawley, and featuring D.W. Griffith in a leading role, was entirely derived from a waxwork group in New York's Eden Musee, Mayer offers pictorial and textual evidence that the film was taken from this theatrical source.

Amphibians, Reptiles, Birds and Mammals of the York River

The York River and its watershed support many natural vegetative communities, from aquatic grass beds to tidal marshes to a variety of woodlands. These communities support a wide variety of resident and migratory amphibians, reptiles, birds and mammals. There are eight families and 26 species of amphibians and ten families and 36 species of reptiles represented within the York River watershed. All three species of sea turtles are protected under the Endangered Species Act and the Northern diamond-backed terrapin is a species of concern. Approximately 230 bird species, resident and migratory, have been recorded within the Chesapeake Bay area. Over 50 families and 190 species of birds have been observed along the estuarine environments of the York River. Specific Reserve components support Bald Eagle nests and Great Blue Heron rookeries. Nineteen families and 50 species of mammals are represented within the York River and its watershed. Of special note is the infrequent occurrence of large marine mammals, such as the bottlenose dolphin and manatee, within the lower York River region.

Cave, City, and Eagle's Nest: An Interpretive Journey through the Mapa de Cuauhtinehan No. 2. Edited by David Carrasco and Scott Sessions. Albuquerque: University of New Mexico Press, 2007. Pp. xxi, 479. Illustrations. Notes. Bibliography. Index. Facsimile map. $100.00 cloth.

Cave, City, and Eagle's Nest: An Interpretive Journey through the Mapa de Cuauhtinehan No. 2. Edited by David Carrasco and Scott Sessions. Albuquerque: University of New Mexico Press, 2007. Pp. xxi, 479. Illustrations. Notes. Bibliography. Index. Facsimile map. $100.00 cloth. - Volume 66 Issue 2

Cave, City, and Eagle's Nest: An Interpretive Journey through the Mapa de Cuauhtinehan No. 2. Edited by David Carrasco and Scott Sessions. Albuquerque: University of New Mexico Press, 2007. Pp. xxi, 479. Illustrations. Notes. Bibliography. Index. Facsimile map. $100.00 cloth.

Cave, City, and Eagle's Nest: An Interpretive Journey through the Mapa de Cuauhtinehan No. 2. Edited by David Carrasco and Scott Sessions. Albuquerque: University of New Mexico Press, 2007. Pp. xxi, 479. Illustrations. Notes. Bibliography. Index. Facsimile map. $100.00 cloth.

Arthropods in the nests of lesser spotted eagle (Aquila pomarina)

In 2001-2007, altogether 57 nests of lesser spotted eagle were collected in the Orava region in northwestern Slovakia and four groups of arthropods were extracted from them. Richest in number of species and individuals were mites (23 species, 17,500 ind.), followed by beetles (12 species, 725 ind.), whereas pseudoscorpions were represented only by Pselaphochernes scorpioides (39 ind.) and fleas by Ceratophyllus garei (3 ind.). Unlike nests of other birds, free-living mites predominated in the nests fauna (83% of individuals), followed by nidicolous species with more or less free relationship to the nests, while parasitic species represented only a negligible part of the fauna. For the first time we observed phoresy of Nenteria pandioni, a specific and abundant mite in the eagles' nests, on the nidicolous staphylinid Haploglossa puncticollis. The beetle fauna in the nests was much poorer than in nests of other birds. The predatory H. puncticollis was dominant in the nests (83%) and occurred continuously during the whole investigation period. Other beetles, even the widely distributed nidicols such as the histerid Gnathoncus buyssoni, were found rarely in nests. Predators were also the only abundant trophic group of beetles in the nests, while other trophic groups of beetles abundantly co-occur in nests of majority of other birds. The occurrence of all beetles was very unevenly distributed during the investigation period, but was positively correlated with occurrence of mites. The relatively low number of species and individuals of mites and beetles in the lesser spotted eagle nests resulted from their position on tree tops, at a height of 20-30 m and their quick drying out by sun and wind. It was also indicated by an enormously low number of species and individuals of mycetophagous beetles, which represent a significant component of the fauna in nests of other birds.

Spatial prediction of species’ distributions from occurrence-only records: combining point pattern analysis, ENFA and regression-kriging

A computational framework to map species’ distributions (realized density) using occurrence-only data and environmental predictors is presented and illustrated using a textbook example and two case studies: distribution of root vole ( Microtes oeconomus) in the Netherlands, and distribution of white-tailed eagle nests ( Haliaeetus albicilla) in Croatia. The framework combines strengths of point pattern analysis (kernel smoothing), Ecological Niche Factor Analysis (ENFA) and geostatistics (logistic regression-kriging), as implemented in the spatstat, adehabitat and gstat packages of the R environment for statistical computing. A procedure to generate pseudo-absences is proposed. It uses Habitat Suitability Index (HSI, derived through ENFA) and distance from observations as weight maps to allocate pseudo-absence points. This design ensures that the simulated pseudo-absences fall further away from the occurrence points in both feature and geographical spaces. The simulated pseudo-absences can then be combined with occurrence locations and used to build regression-kriging prediction models. The output of prediction are either probabilitiesy of species’ occurrence or density measures. Addition of the pseudo-absence locations has proven effective — the adjusted R-square increased from 0.71 to 0.80 for root vole (562 records), and from 0.69 to 0.83 for white-tailed eagle (135 records) respectively; pseudo-absences improve spreading of the points in feature space and ensure consistent mapping over the whole area of interest. Results of cross validation (leave-one-out method) for these two species showed that the model explains 98% of the total variability in the density values for the root vole, and 94% of the total variability for the white-tailed eagle. The framework could be further extended to Generalized multivariate Linear Geostatistical Models and spatial prediction of multiple species. A copy of the R script and step-by-step instructions to run such analysis are available via contact author’s website.

What happens to ptarmigan when marmots arrive?

Rock ptarmigan is a vulnerable species in the southern Pyrenees, with less than 300 pairs and two unconnected populations. Alpine marmot was introduced in the northern Pyrenees between 1955 and 1988, but they rapidly colonised the southern slopes, with an actual estimated population of around 10,000 individuals. Both species are mainly herbivores, develop their activities on the ground and have their offspring at the same time, so they may compete at various levels. We studied the possible interactions between the two species based on field observations, bibliographic data and Geographical Information System (GIS) analysis. We found that alpine marmot has colonised all habitats occupied by rock ptarmigan in the southern Pyrenees, but their plant diet is absolutely differentiated. We also analysed the composition of golden eagle nests and confirmed that this predator predates the two species. From field observations in areas where the two species have coexisted for more than 10 years, we observed no behavioural interaction between the two species. So, although both species share space and time in the alpine communities, both diet differentiation and probably behavioural avoidance permits their coexistence.

Cave, City and Eagle's Nest: An Interpretive Journey Through the Mapa de Cuauhtinchan No. 2– Edited by Davíd Carrasco and Scott Sessions

Cave, City and Eagle's Nest: An Interpretive Journey Through the <i>Mapa de Cuauhtinchan No. 2</i>– Edited by Davíd Carrasco and Scott Sessions

:Cave, City, and Eagle's Nest: An Interpretive Journey through the Mapa de Cuauhtinchan No. 2

Cave, City, and Eagle's Nest is the culmination of an international research project and series of conferences, organized by the Moses Mesoamerican Archive, focused on the sixteenth-century pictorial manuscript known as the Mapa de Cuauhtinchan No. 2. Painted on bark paper and measuring 109 X 204 centimeters, this extraordinary document contains over seven hundred images and symbols relating the story of the emergence of ancestors at Chicomoztoc (Place of Seven Caves), their migration to the sacred city of Cholula, their foundation and settlement of Cuauhtinchan (Place of the Eagle's Nest), their community's history and claim over the surrounding landscape, and many other occurrences along the way. Dating from around the 1540s, barely two decades after the fall of the Aztecs, the mapa recently underwent extensive physical analysis, conservation, and a systematic photographic survey. These rare images - including sixteen full-size sections and a nearly quarter-size facsimile - accompany fifteen richly illustrated essays that explore the meanings and uses of the document, its complex narrative, and the social and ritual memory of an indigenous community struggling to hold its own in the turbulent atmosphere of early colonial Mexico.