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Jodie M Jawor - One of the best experts on this subject based on the ideXlab platform.
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Similarities in expression of territorial aggression in breeding pairs of Northern Cardinals, Cardinalis Cardinalis
Journal of Ethology, 2020Co-Authors: M. Susan Devries, Caitlin P. Winters, Jodie M JaworAbstract:Avian pairs that defend resources year-round may demonstrate similar territorial behavior. We examined male and female responses of Northern Cardinal pairs to male simulated territorial intrusions. Pair members demonstrated comparable responses towards a male ‘intruder’, as latency to respond and proximity scores were very similar between pair members in the majority of pairs examined. Similarity in territorial behavior could be important in Cardinal pairs for maintaining year-round resources.
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Testosterone might not be necessary to support female aggression in incubating Northern Cardinals
Animal Behaviour, 2015Co-Authors: M. Susan Devries, Caitlin P. Winters, Jodie M JaworAbstract:Testosterone's (T) influence on male aggression has been well established in many vertebrate species, but the impact of T on female aggressive behaviour is poorly understood. Among birds, a link between T and female aggression is plausible, as females of many species exhibit a seasonal peak in T concentrations at the onset of breeding when social instability is greatest and they may have circulating T through much of the breeding season. However, investigations examining the relationship between T and female aggression are few and have yielded conflicting results, with experimentally or endogenously elevated T supporting aggressive behaviour in females of some species but not others, and T elevating with aggression at some points of the reproductive cycle but not others. We examined the relationship between endogenous levels of T and female aggression in the Northern Cardinal, Cardinalis Cardinalis, a resident temperate species in which pairs exhibit prolonged territoriality and females have measurable levels of T year-round, including all stages of reproduction (incubation, nestling feeding, etc.). Using simulated nest intrusions, we assessed aggressive responses of incubating females to intrasexual ‘intruders’ at the nest and quantified T levels after each aggressive encounter. Displays of aggression towards ‘intruders’ varied among females; yet, individuals showing greater levels of aggression did not demonstrate higher levels of T. These results imply that T might not support maternal aggression in this species.
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natural variation in circulating testosterone does not predict nestling provisioning rates in the Northern Cardinal Cardinalis Cardinalis
Animal Behaviour, 2013Co-Authors: Susan M Devries, Jodie M JaworAbstract:Behavioural transitions between territoriality and parental care are necessary for many seasonally breeding vertebrates. Among birds, such transitions can be mediated by the steroid hormone testosterone (T), resulting in a T-mediated behavioural trade-off. This theory is supported by many implantation studies with birds demonstrating that the administration of exogenous T during parental phases can negatively affect offspring care. However, little is known about relationships between naturally circulating levels of T and parental behaviour in wild bird populations. We examined covariation in circulating levels of T (before and after injection of gonadotropin-releasing hormone (GnRH)) and nestling provisioning rates in male and female Northern Cardinals, Cardinalis Cardinalis, a highly aggressive, biparental resident songbird. Results indicate that both sexes had detectable levels of initial T when providing parental care, but only males produced significantly higher elevations of T following GnRH injections. Furthermore, T levels (both initial and following GnRH injections) and nestling provisioning rates did not covary for either sex, and these measures were not correlated between members of breeding pairs. When results of this study are considered with prior work indicating that elevations in T might not be necessary to support male or female aggression in this species, it appears that relationships between circulating T and reproductive behaviour could be more complex for the Cardinal than for many others birds similarly examined. Such findings warrant additional examination of interrelationships between T, aggression and other forms of parental care to assess whether this species engages in T-mediated behavioural trade-offs. Possible alternative mechanisms influencing behaviour in the Cardinal and future directions for research are discussed.
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seasonal and sex related variation in song control nuclei in a species with near monomorphic song the Northern Cardinal
Neuroscience Letters, 2008Co-Authors: Jodie M Jawor, Scott A MacdougallshackletonAbstract:Abstract Studies concerning the song control system (SCS) in songbirds generally focus on males due to their prodigious song production. Both seasonal and age related differences have been found in the size of male SCS regions. Among those studies that have addressed females some level of sexual size dimorphism has been found, with females generally having smaller SCS area than males. Among those species where female song has been studied, typically females either sing much less than males, or they duet with their mates, but in general do not produce independent song. Here we present information on seasonal and sex differences in SCS in the Northern Cardinal ( Cardinalis Cardinalis ) a species where both sexes sing, females sing independent of their mates, and song is produced by males over a prolonged period of time (7–8 months). We collected brains from free-living adult Cardinals, both in the late non-breeding season and during the early breeding season, and measured three song control nuclei; HVC, Area X and RA. There were sex differences in all three areas assessed at the two time points considered. Additionally, there was a seasonal difference in both sexes for all areas assessed. In both time points male SCS nuclei were 1.5–2.0 times larger than female SCS nuclei. These data show that even in those species with independent female song there may still exist sex differences in the SCS nuclei. Similarity in song between the sexes could be related to differences in hormone receptors or hormone levels in the brain, while the small-observed changes in SCS area in males may allow for early breeding season song production and song production outside of the breeding season.
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Multiple ornaments correlate with aspects of condition and behaviour in female Northern Cardinals, Cardinalis Cardinalis
Animal Behaviour, 2004Co-Authors: Jodie M Jawor, Nick Gray, Sara M. Beall, Randall BreitwischAbstract:Male ornamentation in socially monogamous birds has been shown to provide information to potential mates on aspects of condition and behaviour. We studied female ornamentation in the socially monogamous, biparental Northern Cardinal to determine whether expressions of multiple ornaments correlate with aspects of female condition and behaviour. Expressions of the ornamental red-orange bill, red underwing feathers, head crest and blackish face mask were compared to several measures of condition, parental behaviour and intrasexual aggression. Red-orange bill colour of females was correlated with both body size and an index of body condition. Redness of the underwing feathers was correlated with body size, body condition, date of first nest produced and reproductive success. Face mask expression was correlated with both nestling feeding rate and level of intrasexual aggression. The length of head crest feathers did not correlate with any measured aspect of condition or behaviour. These results are consistent with the hypothesis that ornaments in female Cardinals provide redundant information to prospective mates on aspects of female condition and behaviour.
Bobby H Fokidis - One of the best experts on this subject based on the ideXlab platform.
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sources of variation in plasma corticosterone and dehydroepiandrosterone in the male Northern Cardinal Cardinalis Cardinalis ii effects of urbanization food supplementation and social stress
General and Comparative Endocrinology, 2016Co-Authors: Sarah Wright, Bobby H FokidisAbstract:Perturbations in an organism’s environment can induce significant shifts in hormone secretory patterns. In this context, the glucocorticoid (GC) steroids secreted by the adrenal cortex have received much attention from ecologists and behaviorists due to their role in the vertebrate stress response. Adrenal GCs, such as corticosterone (CORT), are highly responsive to instability in environmental and social conditions. However, little is understood about how adrenal dehydroepiandrosterone (DHEA) is influenced by changing conditions. We conducted field experiments to determine how circulating CORT and DHEA vary during restraint stress in the male Northern Cardinals (Cardinalis Cardinalis). Specifically, we examined how four different changes in the physical (urbanization and food availability) and social (territorial conflict, distress of a mate) environment affect CORT and DHEA levels. The majority of Cardinals responded to restraint stress by increasing and decreasing CORT and DHEA, respectively, however this depended on sampling context. Cardinals sampled from urban habitats had both lower initial and restraint stress CORT concentrations, but a comparable DHEA pattern to those sampled from a forest. Supplementing food to territorial males did not alter circulating initial DHEA or CORT concentrations nor did it change the response to restraint stress when compared to unsupplemented controls. Exposing Cardinals to varying durations of song playback, which mimics a territorial intrusion, did not affect CORT levels, but did attenuate the DHEA response to restraint stress. Examining a larger dataset of males captured before, after or at the same time as their female mate, allowed us to address how the stress of a captured mate affected the male’s CORT and DHEA response. Males showed elevated initial and restraint CORT and DHEA when their female mate was captured first. Taken together, these data demonstrate that both CORT and DHEA secretion patterns depends on environmental, and particularly current social conditions.
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sources of variation in plasma corticosterone and dehydroepiandrosterone in the male Northern Cardinal Cardinalis Cardinalis i seasonal patterns and effects of stress and adrenocorticotropic hormone
General and Comparative Endocrinology, 2016Co-Authors: Bobby H FokidisAbstract:The secretion of steroids from the adrenal gland is a classic endocrine response to perturbations that can affect homeostasis. During an acute stress response, glucocorticoids (GC), such as corticosterone (CORT), prepare the metabolic physiology and cognitive abilities of an animal in a manner that promotes survival during changing conditions. Although GC functions during stress are well established, much less is understood concerning how adrenal androgens, namely dehydroepiandrosterone (DHEA) are influenced by stress. I conducted three field studies (one experimental and two descriptive) aimed at identifying how both CORT and DHEA secretion in free-living male Northern Cardinals (Cardinalis Cardinalis), vary during acute stress; across different circulations (brachial vs. jugular); in response to ACTH challenge; and during the annual cycle. As predicted, restraint stress increased plasma CORT, but unexpectedly DHEA levels decreased, but the latter effect was only seen for blood sampled from the jugular vein, and not the brachial. The difference in DHEA between circulations may result from increased neural uptake of DHEA during stress. Injection with exogenous adrenocorticotropic hormone (ACTH) increased CORT concentrations, but failed to alter DHEA levels, thus suggesting ACTH is not a direct regulator of DHEA. Monthly field sampling revealed distinct seasonal patterns to both initial and restraint stress CORT and DHEA levels with distinct differences in the steroid milieu between breeding and non-breeding seasons. These data suggest that the CORT response to stress remains relatively consistent, but DHEA secretion is largely independent of the response by CORT. Although CORT functions have been well-studied in wild animals, little research exists for the role of DHEA and their variable relationship sets the stage for future experimental research addressing steroid stress responses.
Scott A Macdougallshackleton - One of the best experts on this subject based on the ideXlab platform.
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seasonal and sex related variation in song control nuclei in a species with near monomorphic song the Northern Cardinal
Neuroscience Letters, 2008Co-Authors: Jodie M Jawor, Scott A MacdougallshackletonAbstract:Abstract Studies concerning the song control system (SCS) in songbirds generally focus on males due to their prodigious song production. Both seasonal and age related differences have been found in the size of male SCS regions. Among those studies that have addressed females some level of sexual size dimorphism has been found, with females generally having smaller SCS area than males. Among those species where female song has been studied, typically females either sing much less than males, or they duet with their mates, but in general do not produce independent song. Here we present information on seasonal and sex differences in SCS in the Northern Cardinal ( Cardinalis Cardinalis ) a species where both sexes sing, females sing independent of their mates, and song is produced by males over a prolonged period of time (7–8 months). We collected brains from free-living adult Cardinals, both in the late non-breeding season and during the early breeding season, and measured three song control nuclei; HVC, Area X and RA. There were sex differences in all three areas assessed at the two time points considered. Additionally, there was a seasonal difference in both sexes for all areas assessed. In both time points male SCS nuclei were 1.5–2.0 times larger than female SCS nuclei. These data show that even in those species with independent female song there may still exist sex differences in the SCS nuclei. Similarity in song between the sexes could be related to differences in hormone receptors or hormone levels in the brain, while the small-observed changes in SCS area in males may allow for early breeding season song production and song production outside of the breeding season.
Randall Breitwisch - One of the best experts on this subject based on the ideXlab platform.
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Multiple ornaments correlate with aspects of condition and behaviour in female Northern Cardinals, Cardinalis Cardinalis
Animal Behaviour, 2004Co-Authors: Jodie M Jawor, Nick Gray, Sara M. Beall, Randall BreitwischAbstract:Male ornamentation in socially monogamous birds has been shown to provide information to potential mates on aspects of condition and behaviour. We studied female ornamentation in the socially monogamous, biparental Northern Cardinal to determine whether expressions of multiple ornaments correlate with aspects of female condition and behaviour. Expressions of the ornamental red-orange bill, red underwing feathers, head crest and blackish face mask were compared to several measures of condition, parental behaviour and intrasexual aggression. Red-orange bill colour of females was correlated with both body size and an index of body condition. Redness of the underwing feathers was correlated with body size, body condition, date of first nest produced and reproductive success. Face mask expression was correlated with both nestling feeding rate and level of intrasexual aggression. The length of head crest feathers did not correlate with any measured aspect of condition or behaviour. These results are consistent with the hypothesis that ornaments in female Cardinals provide redundant information to prospective mates on aspects of female condition and behaviour.
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Plumage brightness as an indicator of parental care in Northern Cardinals
Animal Behaviour, 1998Co-Authors: Susan U. Linville, Randall Breitwisch, Amy J. SchillingAbstract:Good parent and differential allocation models predict relationships between degree of sexual ornamentation and parental care, but relatively few studies have tested these models. The Northern Cardinal,Cardinalis Cardinalis, is a sexually dichromatic species in which both sexes are ornamented. Males have red plumage, and females have tan plumage with limited areas of red feathering. Cardinals were used to address the two models and determine whether plumage brightness signals level of parental care by both sexes. Absolute effort in feeding nestlings by males was not correlated with male breast plumage colour, but effort by females was positively correlated with female underwing plumage colour. Absolute feeding effort by females was also inversely related to brightness of the mate's breast colour. As a consequence, the proportion of a pair's total feedings provided by the male was positively correlated with male breast colour. Proportion of total feedings provided by the female was positively correlated with female wing colour. Feeding efforts (both per nest and per nestling) were correlated between mates, but birds did not mate assortatively in relation to colour. These results support the good parent hypothesis, suggesting colour brightness is a signal of parental care. The results also indicate that ornamentation of both members of the pair may be important determinants of relative efforts in provisioning nestlings by parent birds.
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reproductive success of the Northern Cardinal a large host of brown headed cowbirds
The Condor, 1997Co-Authors: Kevin P Eckerle, Randall BreitwischAbstract:We investigated the effects of brood parasitism by Brown-headed Cowbirds (Molothrus ater) on Northern Cardinal (Cardinalis Cardinalis) reproductive success to test the hypothesis that cowbird hosts of similar size and incubation period to cowbirds are able to raise their own offspring when parasitized. During the breeding seasons of 1993-1995, we collected data on the frequency and intensity of cowbird parasitism, the effect of cowbird parasitism on Cardinal reproductive success, and the defensive response of Cardinals to parasitism. Of the 115 Cardinal nests, 48% were parasitized, and the mean number of cowbird eggs per parasitized nest was 1.3. Nest survival, as calculated by the Mayfield analysis, was higher in parasitized than unparasitized nests across all stages of the nesting cycle. Although female cowbirds removed significantly more Cardinal eggs per parasitized than unparasitized nest, parasitized Cardinals did not suffer losses attributable to reduced hatching success or nestling competition. The growth rates of Cardinals in parasitized and unparasitized nests did not differ, nor did that of Cardinals and cowbirds in the same nest. We detected Cardinal defensive response at only three (5%) parasitized nests. These data suggest that this population of Cardinals pays only a slight cost in being parasitized by cowbirds, which may explain the lack of defensive response.
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nestling provisioning by the extremely dichromatic Northern Cardinal
The Wilson Journal of Ornithology, 1997Co-Authors: Tamatha S Filliater, Randall BreitwischAbstract:We measured feeding rates of nestlings during 143 h of observation on 23 pairs of the extremely dichromatic and socially monogamous Northern Cardinal (Cardinalis Cardinalis). Males fed at higher rates than did females, both when measured as rate per brood and as rate per nestling. Only males maintained their feeding rate per nestling with an increase in brood size and increased their feeding effort as nestlings aged. Feeding efforts by mates were correlated, even when controlling for the effects of brood size. These results provide support both for hypotheses predicting substantial male parental effort in socially monogamous birds and for the assortative mating hypothesis, predicting that birds of similar quality mate with one another. We reject the deflection hypothesis predicting low paternal provisioning effort in strongly dichromatic species and conclude that any cost to male car-
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predation on Northern Cardinal nests does choice of nest site matter
The Condor, 1994Co-Authors: Tamatha S Filliater, Randall Breitwisch, Paul M NealenAbstract:The fates of 12 1 nests of Northern Cardinals (Cardinalis Cardinalis) in south- western Ohio were determined in 199 1 and 1992. Success rate was only 1 So/o, estimated by the Mayfield method. All failed nests were known or suspected to have heen preyed upon. Several hypotheses to explain differences between the location of successful and failed nests were tested. None of those considered explained why the contents of particular nests were taken. We propose that a high incidence of predation by a rich guild of nest predators precludes the existence of predictably safe nest sites for Cardinals. Instead, Cardinals appear simply to be well-adapted to renest rapidly in response to the near randomness of nest predation. A similar adaptation may characterize many passerines.
Amanda D. Rodewald - One of the best experts on this subject based on the ideXlab platform.
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Exotic shrubs as ephemeral ecological traps for nesting birds
Biological Invasions, 2010Co-Authors: Amanda D. Rodewald, Daniel P. Shustack, Lauren E. HitchcockAbstract:Certain exotic plants may increase risk of nest predation, and, in this way, may act as ecological traps. We hypothesized that the greater vulnerability to predation was a consequence of either (1) reduced nest height due to architectural differences among plant species or (2) seasonal changes in the distribution of nests among forest strata. To test this, we examined temporal variation in nest survival of 888 nests of Northern Cardinal ( Cardinalis Cardinalis ) in native substrates and two exotic shrubs ( Lonicera maackii and Rosa multiflora ) in Ohio, USA, 2001–2006. We evaluated evidence for an ecological trap by monitoring the annual reproductive productivity of 245 breeding pairs of Cardinals. Only nests in Rosa experienced relatively constant survival rates across the season, whereas probability of survival increased over the season for nests in other substrates. Interestingly, the relative vulnerability of nests in different substrates varied across the season. Most strikingly, nests in Lonicera in early spring showed the lowest survival rates but exceeded survival rates of nests in native substrates late in the season. Nest height failed to explain seasonal changes in nest survival, as only nests in native plants significantly increased in height as the season progressed. Rather, predation risk seemed to be a function of the proportion of nests within each substrate, as illustrated by the decreased predation in Lonicera as the relative proportion of nests in native substrates increased. The patterns of temporal variation in predation risk that we detected show that impacts of Lonicera are not a function of plant architecture alone and may be related to leaf phenology, changes in nest density, nest site location, and/or nest synchrony. Examination of the reproductive productivity of Cardinals showed that pairs that made their first nest attempt in Lonicera fledged 20% fewer Cardinal young than birds that began the season using other substrates. Thus, we suggest that exotic plants may represent an ephemeral ecological trap for certain nesting birds, where negative effects persist only during certain periods.
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Are urban forests ecological traps for understory birds? An examination using Northern Cardinals
Biological Conservation, 2006Co-Authors: Lionel F.v. Leston, Amanda D. RodewaldAbstract:Abstract Many studies have reported increased numbers of certain synanthropic species in urbanizing landscapes, but few have evaluated if urban habitats constitute ecological traps for these species. The Northern Cardinal (Cardinalis Cardinalis) was used as a model species to evaluate if urban riparian forests might act as ecological traps for understory-nesting birds. Cardinals were surveyed within 2-ha riparian forest plots within rural (n = 6) and urban (n = 6) landscapes in Ohio USA during breeding and non-breeding seasons 2003–2005. Cues used by Cardinals to select habitats were identified based on measurements surrounding 219 nests and in 106 randomly-located plots and 96 systematically-located plots. Productivity of 161 Cardinal pairs and survival of 180 adults were monitored from late March–September, 2003–2005. Cardinals were 1.7× (in the breeding season) to nearly 4× (in non-breeding season) more abundant in urban than rural forests, and the results suggest that these differences in abundance stemmed from urban-associated changes in habitat and microclimate features used by Cardinals to select habitats. Most notably, Cardinals were strongly associated with dense understory vegetation and warmer minimum January temperatures, both of which were promoted as urban development increased within the landscapes surrounding riparian forests. Although other studies suggest mismatches between the habitat cues used by Cardinals and how those features affect nesting success (e.g., higher nest predation in exotic shrubs), these results provide no evidence that urban forests were acting as ecological traps for Cardinals. Instead, Cardinals in urban and rural forests had similar numbers of nesting attempts, young fledged over the breeding season, and apparent annual survival rates. Thus, these findings do not support for the idea that urban forests in central Ohio represent ecological traps for synanthropic understory birds.