Red-Shouldered Hawk Study in Southern Ohio

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CAUSES OF MORTALITY AND FAILURE OF SUBURBAN RED-SHOULDERED HAWK  ( Buteo lineatus) NESTS.
  


          SARA J. MILLER, CHERYL R. DYKSTRA, MELINDA M. SIMON, JEFFREY L. HAYS, AND JAMES C. BEDNARZ

Abstract.     There have been no detailed studies of predator or non-predator causes of mortality and failure at nests of the Red-shouldered Hawk (Buteo lineatus), and identification of such causes has been largely speculative.  There is ample information about rates of nest success, defined as the fledging of ≥1 nestling from a nest, but this measure of reproductive rate is limited in its scope.  Fledging success, measured by quantifying total nestlings lost or fledged is a more informative assessment of reproductive success, but is not often reported.  We used video monitoring of suburban Red-shouldered Hawk nests to identify causes of mortality or failure.  Eight of 25 nests failed completely (32%), and 17 were successful (68%).  However, nine of the 17 successful nests experienced some nestling mortality, and the fledging success of individual nestlings (= 67) was only 58%, as 28 nestlings (42%) died before fledging.  Causes of mortality or nest failure included depredation of an incubating female parent at one nest and of nestlings at multiple nests by Great Horned Owls (Bubo virginianus), depredation of nestlings by raccoons (Procyon lotor), disturbance by eastern gray squirrels (Sciurus carolinensis), unexplained disappearance of female parents, starvation of nestlings, and nestlings falling from the nest.  These results provide a thorough and accurate account of reproductive success, and valuable identification of predator and non-predator causes of nestling mortality or nest failure throughout the nesting period.

 

The Condor 102:401-408, 2000


NEST SITE SELECTION AND PRODUCTIVITY OF SUBURBAN RED-SHOULDERED HAWKS IN SOUTHERN OHIO

           
                          

CHERYL R. DYKSTRA,  JEFFREY L. HAYS,   F. BERNARD DANIEL,

AND  MELINDA M. SIMON

Abstract.     We measured nest site selection and productivity of suburban-nesting Red-shouldered Hawks (Buteo lineatus) in southwestern Ohio and rural-nesting Red-shouldered Hawks in south-central Ohio. At both the suburban and the rural locations, nest sites had greater canopy height and overall tree basal area than paired random plots, and were located closer to water than were paired random plots. Nest trees also had greater diameter and height than random plot-center trees. Reproductive rates at suburban and rural sites were similar, averaging 2.6-3.1 nestlings per successful nest. Results indicated that suburban nesting Red-shouldered Hawks were very similar to rural-nesting hawks in both nest site selection and productivity, suggesting that Red-shouldered Hawks were habituated to their suburban environs.
 

The Condor 103:652-656,  2001
 

CORRELATION OF RED-SHOULDERED HAWK ABUNDANCE AND MACRO HABITAT CHARACTERISTICS IN SOUTHERN OHIO

 

CHERYL R. DYKSTRA,   F. BERNARD DANIEL,   JEFFREY L. HAYS,  

AND MELINDA M. SIMON

 
Abstract.    We measured an index of Red-shouldered Hawk (Buteo lineatus) abundance along streams in southern Ohio and related differences in abundance index to landscape-scale habitat characteristics within the surveyed areas. Fifteen study sites, each a 5.8-km reach of a permanent stream, were surveyed four times using broadcasts of Red-shouldered Hawk calls and Red-tailed Hawk (Buteo jamaicensis) calls. We determined the land cover types in a corridor surrounding each surveyed area using a GIS land cover data grid, and counted the number of small ponds within each corridor. We calculated hawk response rate for each species as the mean number of visual or aural detections per survey. Red-shouldered Hawk response rate was inversely correlated to Red-tailed Hawk response rate (r = -0.52, P < 0.04), and was positively correlated to the number of small ponds within each stream corridor (r = 0.77, P < 0.01), suggesting that the number of small ponds was an important factor associated with Red-shouldered Hawk abundance.
 

Wilson Bulletin 113:308–316, 2001
 

HOME RANGE AND HABITAT USE OF SUBURBAN RED-SHOULDERED HAWKS IN SOUTHWESTERN OHIO

 

CHERYL R. DYKSTRA JEFFREY L. HAYS,   F. BERNARD DANIEL,

AND MELINDA M. SIMON

 

Abstract.   We measured the home ranges and habitat use of 11 Red-shouldered Hawks (Buteo lineatus) during the breeding season and 9 during the nonbreeding season in suburban Ohio, using standard telemetry techniques. Mean home ranges, calculated using the adaptive kernel method (95% isopleth), were 90 ha during the breeding season, 189 ha during the nonbreeding season, and 165 ha for the annual home range. Males and females did not differ significantly in home range size. We examined habitat use by hawks by classifying the habitat where birds were observed perching. Habitat used by hawks differed significantly from that available within home ranges for all birds tested. Most Red-shouldered Hawks used riparian zones and pond edges more than expected, based on availability of such habitats within their home ranges; residential areas and lawns were used less than expected or in proportion to their availability.
 

The Journal of Raptor Research  37:177-187, 2003 
 

BEHAVIOR AND PREY OF NESTING RED-SHOULDERED HAWKS IN SOUTHWESTERN OHIO

 

CHERYL R. DYKSTRA,  JEFFREY L. HAYS,  F. BERNARD DANIEL,

 AND  MELINDA M. SIMON
 

Abstract.   We used direct observations to quantify prey types, prey delivery rate, and adult and nestling behavior at nests of Red-shouldered Hawks
(Buteo lineatus) in suburban Southwestern Ohio. Twenty-one nests were observed for 256 hr in 1997-2001.Small mammals made up the largest percentage of the identified prey (31.5%), followed by reptiles (22.7%), invertebrates (18.8%), amphibians (17.7%), birds (6.9%), and fish (2.5%). Season-long prey delivery rate averaged 3.4 prey items delivered per 4-hr observation period, or 116 g biomass delivered per 4-hr observation period.  Weekly prey delivery rate showed no correlation with the age of the nestlings (P > 0.05). Adult attendance at the nest and time adults spent brooding nestlings both were negatively correlated with nestling age (P < 0.05). Time adults spent feeding nestlings was negatively correlated with nestling age (R
²= 0.92, P = 0.002), while time nestlings spent feeding themselves was positively correlated with nestling age (R²= 0.92, P = 0.003). These data may serve as a baseline for assessing  prey delivery rates and behavior of populations of Red-shouldered Hawks throughout the lower Midwest.
 

The Journal Raptor Research 38:304-311,  2004
 

DISPERSAL AND MORTALITY OF RED-SHOULDERED HAWKS BANDED IN OHIO

 

CHERYL R. DYKSTRA,  JEFFREY L. HAYS,  MELINDA M. SIMON,  JOHN B. HOLT, JR.

G. RONALD AUSTING,  AND  F. BERNARD DANIEL
 

Abstract.   We banded nestling Red-shouldered Hawks (Buteo lineatus) in southwestern Ohio and northern Kentucky (SW OHIO, hereafter) to examine movements and determine causes of mortality in this suburban population. For comparison, we examined band recovery records for nestling Red-shouldered Hawks banded in rural northern Ohio. Of 899 nestlings banded in SW OHIO from 1955-2002, 43 (4.8%) were encountered (dead or alive) some time after fledging. Mean distance from natal nest at time of encounter was 38.5 km and was not correlated with hawk age (P > 0.58). Distance from natal nest did not differ for hawks of three age classes or between those encountered in the breeding and nonbreeding seasons ( P > 0.13). Cumulative exponential distribution (CED) analysis of distance from natal nest at time of encounter indicated that 50% of SW OHIO Red-shouldered Hawks were found <15 km from their natal nest, 75% were <29 km away, and 95% were <62 km away. Mean age of hawks recovered dead was 1.9 yr (N = 31). CED analysis of age at recovery indicated that 50% of Red-shouldered Hawks were dead by age 1.2 yr, 75% by 2.4 yr, and 95% by 5.2 yr. SW OHIO hawks did not differ from hawks banded in northern Ohio in either distance from natal nest or age at recovery.
 

The Wilson Journal of Ornithology 121:207–210, 2009

SELECTION OF FRESH VEGETATION FOR NEST LINING BY RED-SHOULDERED HAWKS


CHERYL R. DYKSTRA,  JEFFREY L. HAYS,  AND  MELINDA M. SIMON
 
 

Abstract.   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 (Presinosa), 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.
 

The Condor 111:177–182, 2009
 

SPATIAL AND TEMPORAL VARIATION IN REPRODUCTIVE RATES OF THE RED-SHOULDERED HAWK
IN SUBURBAN  AND RURAL OHIO

 
CHERYL R. DYKSTRA,  JEFFREY L. HAYS, AND  MELINDA M. SIMON
 
Abstract.   We measured the reproductive rate of  Red-shouldered Hawks (Buteo lineatus) nesting in suburban southwestern Ohio and in a rural forested region in Hocking Hills, southeastern Ohio, from 1997 to 2005. In the suburban region, the reproductive rate varied greatly from nest to nest, less so from year to year, indicating that some nest areas consistently produced more young than others. The most productive 25% of nest areas produced 44% of all the nestlings in the study, whereas the least productive 25% of nest areas produced only 7% of all nestlings.  In the rural area, the reproductive rate varied significantly from year to year, less so from nest area to nest area. Overall reproductive rates in the two study areas differed only in 2000. We suggest that differences among the nest areas in reproductive rate likely indicate differences in habitat quality of individual nest areas, whereas differences among years likely reflect regional factors that influence nesting birds, such as weather.

Molecular Phylogenetics and Evolution 49:988–996, 2008

COMPARATIVE PHYLOGEOGRAPHY AND POPULATION GENETICS WITHIN BUTEO LINEATUS REVEALS EVIDENCE OF DISTINCT EVOLUTIONARY LINEAGES

 

JOSHUA M. HULL,  BRADLEY  N. STROBLE,  CLINT W. BOAL,  ANGUS C. HULL,  CHERYL R. DYKSTRA,

 AMANDA M. IRISH,  ALLEN M. FISH, AND HOLLY B. ERNEST


Abstract.   Traditional subspecies classifications may suggest phylogenetic relationships that are discordant with evolutionary history and mislead evolutionary inference. To more accurately describe evolutionary relationships and inform conservation efforts, we investigated the genetic relationships and demographic histories of Buteo lineatus subspecies in eastern and western North America using 21 nuclear microsatellite loci and 375-base pairs of mitochondrial control region sequence. Frequency based analyses of mitochondrial sequence data support significant population distinction between eastern (B. l. lineatus/alleni/ texanus) and western (B. l. elegans) subspecies of B. lineatus. This distinction was further supported by frequency and Bayesian analyses of the microsatellite data. We found evidence of differing demographic histories between regions; among eastern sites, mitochondrial data suggested that rapid population expansion occurred following the end of the last glacial maximum, with B. l. texanus population expansion preceding that of B. l. lineatus/alleni. No evidence of post-glacial population expansion was detected among western samples (B. l. elegans). Rather, microsatellite data suggest that the western population has experienced a recent bottleneck, presumably associated with extensive anthropogenic habitat loss during the 19th and 20th centuries. Our data indicate that eastern and western populations of B. lineatus are genetically distinct lineages, have experienced very different demographic histories, and suggest management as separate conservation units may be warranted.
 

   

The Journal of Raptor Research 46:190 - 2009

 

    Habitats of Suburban Barred Owls (Strix varia) and Red-shouldered Hawks (Buteo lineatus) in Southwestern Ohio

          

Cheryl R. Dykstra, Melinda M. Simon, F. Bernard Daniel, and Jeffrey L. Hays


Abstract.  Little is known about the habitat and ecology of suburban Barred Owls (Strix varia), a species sometimes considered the nocturnal equivalent of Red-shouldered Hawks (Buteo lineatus). We compared nesting habitat of Barred Owls to that of Red-shouldered Hawks nesting in suburban and urban areas, in and near the city of Cincinnati, Ohio, to determine whether any features distinguished owl nest sites from hawk nest sites. We characterized habitat and land-cover metrics in circular plots of 100 ha and 15 ha, centered on the owl and hawk nests, using ATtiILa software operating within a GIS environment. For the 100-ha plots, the primary cover type in the plots surrounding nests of both species was forest, 41.4 ± 3.4% for Barred Owl plots and 45.9 ±3.4% for Red-shouldered Hawk plots, followed by low-density residential land: 29.8 ± 4.8% of the Barred Owl plots and 29.3 ±3.7% of the Red-shouldered Hawk plots. Pasture composed <15% of the plot area for both species and the remainder of the cover types contributed even less. Values of land-cover percentages and metrics did not differ between the species (P > 0.05), for either the large plots or the small (15-ha) plots. Using stepwise binary logit regression analysis, we found that no variables discriminated owl plots from hawk plots. We concluded, based on our methodology, that habitat of suburban Barred Owls differed little from habitat of suburban Red-shouldered Hawks in southwestern Ohio.


The Journal of Raptor Research 46(4):357-364. 2012   

 

SEXING ADULT AND NESTING RED-SHOULDERED HAWKS USING MORPHOMETRICS AND MOLECULAR TECHNIQUES

 

CHERYL R. Dykstra, HERMAN  L. MAYS JR,  Jeffrey L. Hays, Melinda M. Simon, AND ANN R. WEGMAN
 
Abstract.—Sexing of raptors is important for understanding their ecology and demography. Males and females of monomorphic species such as Red-         Shouldered Hawks (Buteo lineatus) may be distinguished using molecular and morphometric techniques. We collected blood samples and morphometric measurements from adult and nestling Red-shouldered Hawks in southern Ohio. We determined sex via amplification of the sex-linked chromo-helicase-DNA-binding gene and polymerase chain reaction. We used a suite of morphometric measurements to generate a recursive partitioning classification tree and in a linear discriminant analysis to determine the sex of adults and nestlings. For adults, the recursive partitioning tree only utilized mass to distinguish sexes, with an overall successful classification rate of 94%. For nestling hawks aged approximately 3 wk and older, mass and toepad (footpad) length were used to distinguish the sexes, with an overall successful classification rate of 91%. The ability to sex adults and nestlings in the field is valuable for studies of dispersal, survival, and behavior.
 

 

                                                                           The Wilson Journal of Ornithology, 124(46):190-200. 2012

Protocalliphora
(Diptera: Calliphoridae) Infestations of Nestling  Red-shouldered Hawks in Southern Ohio

Cheryl R. Dykstra , Jeffrey L. Hays , Melinda M. Simon , and Ann R. Wegman

Abstract.—We examined nestling Red-shouldered Hawks (Buteo lineatus) in 56 nests (147 nestlings) in suburban southwestern Ohio and in 25 nests (67 nestlings) in rural forested Hocking Hills in south-central Ohio, ~ 180 km east of southwestern Ohio. Fifteen of 25 nests in Hocking Hills had Protocalliphora avium larvae on one or more nestlings and/or pupae in the nest material. Nineteen nestlings had larvae in one or both ears, an additional 14 had evidence of larvae outside the ears, 32 were not visibly parasitized, and two were not examined or their status was not reported; in contrast, no nests and no nestlings were parasitized in southwestern Ohio. Reproductive rate (young fledged/nest) did not differ between southwestern Ohio and Hocking Hills (2.4 ± 0.1 young/nest at southwestern Ohio vs. 2.7 ± 0.2 at Hocking Hills; P = 0.214). Parasitized nests at Hocking Hills were no more likely to have been used in the previous breeding season than non-parasitized nests (χ2 = 0.903, P = 0.342, n = 22). Similarly, number of young fledged/nest at parasitized nests did not differ from that at non-parasitized nests within Hocking Hills (U = 75.0, P = 1.00, n = 25; mean (± SE) number of young = 2.7 ± 0.3 vs. 2.7 ± 0.3 at parasitized and non-parasitized nests, respectively). The Protocalliphora loads we observed did not appear to have a negative effect on the fledging rate of nestling Red-shouldered Hawks; however, we did not assess any other potential effects of parasitism.
 

 

The Wilson Journal of Ornithology, 125(3):630-637. 2013.
 


USING MORPHOMETRIC  MEASUREMENTS TO ESTIMATE AGE  OF NESTLING RED- SHOULDERED HAWKS IN TWO EASTERN POPULATIONS

BRENDA L. PENAK,  CHERYL  R. DYKSTRA, SARA J. MILLER, AND DAVID M. BIRD

 

Abstract.—Nestling growth may be used to estimate age of nestling raptors, which is valuable for investigating hatch order dynamics and nestling behavior, as well as assessing reproductive rate and back-calculating hatching date. To estimate nestling age, the most valuable parameter to measure growth is one that does not vary greatly with environmental factors, and ideally is applicable over a wide range of populations. We measured growth of nestling Red-shouldered Hawks (Buteo lineatus) in Quebec, Canada, from ages 3 days to near fledging (38 days old), and compared growth of several parameters in different size broods. As a validation study, we measured similar parameters one time in known-age nestling Red-shouldered Hawks in southwestern Ohio. Growth rates for tarsus length, bill length, and tail length differed between nestlings in broods of one and three young, respectively, in Quebec. However, mass gain and growth of secondary feathers (mean length of first and second secondaries) did not differ between brood sizes, although mass gain was more variable than secondary growth. These results suggested that secondary feather length was the most valuable parameter for estimating nestling age in Red-shouldered Hawks. Comparing Ohio nestlings to Quebec nestlings, we found that growth of secondary feathers differed significantly, with Ohio nestlings having smaller secondary length, relative to age estimate. Application of the equation generated with the Quebec data to estimate the age of the Ohio nestlings based on secondary length resulted in estimates that were 2.3 ± 0.3 days (range 0.25 - 4.5 days; n = 22) younger than the Ohio nestlings’ actual ages. Based on this validation study, we suggest that the use of the Quebec age-secondary length equation to estimate age for nestling Red-shouldered Hawks in other parts of eastern North America is acceptable, though with the caveat that such estimates are associated with potential small errors. Received 24 January 2013. Accepted 3 May 2013.

 

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