scholarly journals Short-term exposure to unmanned aerial vehicles does not alter stress responses in breeding tree swallows

2020 ◽  
Vol 8 (1) ◽  
Author(s):  
Bradley D Scholten ◽  
Abigail R Beard ◽  
Hyeryeong Choi ◽  
Dena M Baker ◽  
Margaret E Caulfield ◽  
...  

Abstract Recent studies suggest that visual and acoustic anthropogenic disturbances can cause physiological stress in animals. Human-induced stress may be particularly problematic for birds as new technologies, such as drones, increasingly invade their low-altitude air space. Although professional and recreational drone usage is increasing rapidly, there is little information on how drones affect avian behavior and physiology. We examined the effects of drone activity on behavior and physiology in adult, box-nesting tree swallows (Tachycineta bicolor). Specifically, we monitored bird behavior during drone flights and in response to a control object and measured telomere lengths and corticosterone levels as indicators of longer-term physiological stress. We predicted that drone-exposed tree swallows would habituate behaviorally after multiple flights, but that telomeres would shorten more quickly and that baseline corticosterone levels would be altered. One significant and two strong, non-significant trends in behavioral assays indicated that adult swallows acted more aggressively towards drone presence compared to a control object, but were slower to approach the drone initially. Swallows were also more reluctant to use nest boxes during drone activity. Tree swallows habituated to drone presence as expected, although the rate of habituation often did not differ between drone-exposed and control groups. Contrary to our prediction, drone activity did not affect telomere length, corticosterone levels, body mass or fledging rates. Overall, our results indicate that a small number of short, targeted, drone flights do not impact tree swallow health or productivity differently than a non-invasive control object. Minor behavioral differences suggest that increasing the frequency of drone use could impact this species. We provide some of the first results addressing how drone activity alters behavioral, physiological and molecular responses to stress in songbirds. A better understanding of these impacts will allow ecologists to make more informed decisions on the use and regulation of new drone technologies.

2001 ◽  
Vol 79 (2) ◽  
pp. 346-353 ◽  
Author(s):  
Krista Thomas ◽  
Dave Shutler

Many studies fail to show relationships between ectoparasite loads and nestling growth rates. One explanation is that parent birds increase feeding rates to compensate for nestling energetic losses to ectoparasites. Nestling begging behaviours could signal need to parents. Accordingly, we tested whether higher flea and blow fly loads in tree swallow (Tachycineta bicolor) nests were associated with smaller nestlings, higher parental feeding rates, and increased nestling begging intensity. The study area was the Gaspereau Valley of Nova Scotia, Canada. When nestlings were 10 days old, parental feeding rates and nestling begging intensity were measured with tape recorders. At 13 days of age, nestlings were weighed and measured. Within 2 days of fledging, nest material was removed from nest boxes and enumerated for adult fleas and blow fly pupae. After including brood size and date of first egg as covariates in general linear models, no significant relationships were found between ectoparasite loads and nestling size, parental feeding rate, or nestling begging intensity. Our results suggest that nestling tree swallows were able to buffer the effects of naturally occurring ectoparasite loads without significant help from their parents. Low levels of virulence may have resulted from relatively benign weather during the study, low numbers of ectoparasites, selection on ectoparasites to avoid killing their hosts, and host defences.


1994 ◽  
Vol 72 (2) ◽  
pp. 330-333 ◽  
Author(s):  
George A. Lozano

Male tree swallow (Tachycineta bicolor) territory owners and floaters were compared in terms of size and nutritional condition to test the resource holding potential hypothesis. Owners were larger than floaters when compared using six morphological measurements. There were no differences in dry mass, ash, or fat content, but territory owners were heavier and had larger protein reserves than floaters. Territory owners may be those individuals who win intrasexual conflicts for the possession of nest boxes, or those who, because of their better nutritional condition, can arrive at the breeding grounds earlier to secure a territory.


1990 ◽  
Vol 68 (5) ◽  
pp. 1046-1052 ◽  
Author(s):  
Raleigh J. Robertson ◽  
Wallace B. Rendell

Several studies concerned with mate choice, reproductive performance, and life history strategies have been conducted with secondary cavity nesting birds breeding in nest boxes. Although the need for comparative studies has been recognized, populations breeding in nest boxes often have not been compared with those breeding in natural cavities. We compared the ecology of Tree Swallows breeding in nest boxes and natural cavities to determine if nest box populations of Tree Swallows are accurate models of natural populations. Two nest site characteristics, nest site dispersion and cavity height, were similar for birds in both nesting environments. Greater cavity entrance area at natural cavities resulted in increased interspecific competition in natural populations, involving larger competitors, more species, and a greater abundance of each species. Clutch size was smaller in natural cavities compared with nest boxes, likely because floor area was smaller in natural cavities. Fledging success did not differ between populations. Disproportionately more after-second-year females bred in nest boxes, and more second-year females bred in natural cavities, as estimated by a model of Tree Swallow survivorship. Tree Swallows settle at nest boxes before natural cavities in our study area, perhaps as a result of the greater potential for reproductive success and reduced interspecific competition in the nest boxes as opposed to natural cavities. For some aspects of the ecology of secondary cavity nesters, nest boxes do not provide an accurate representation of natural populations. Therefore, evolutionary interpretations of nest box studies should be compared with observations of birds in natural environments.


2008 ◽  
Vol 16 (3) ◽  
pp. 112-115 ◽  
Author(s):  
Stephan Bongard ◽  
Volker Hodapp ◽  
Sonja Rohrmann

Abstract. Our unit investigates the relationship of emotional processes (experience, expression, and coping), their physiological correlates and possible health outcomes. We study domain specific anger expression behavior and associated cardio-vascular loads and found e.g. that particularly an open anger expression at work is associated with greater blood pressure. Furthermore, we demonstrated that women may be predisposed for the development of certain mental disorders because of their higher disgust sensitivity. We also pointed out that the suppression of negative emotions leads to increased physiological stress responses which results in a higher risk for cardiovascular diseases. We could show that relaxation as well as music activity like singing in a choir causes increases in the local immune parameter immunoglobuline A. Finally, we are investigating connections between migrants’ strategy of acculturation and health and found e.g. elevated cardiovascular stress responses in migrants when they where highly adapted to the German culture.


2020 ◽  
Vol 32 (5) ◽  
pp. 1888-1898
Author(s):  
Melissa J. Hagan ◽  
Danielle S. Roubinov ◽  
W. Thomas Boyce ◽  
Nicole R. Bush

AbstractThere is emerging evidence that the development of problematic aggression in childhood may be associated with specific physiological stress response patterns, with both biological overactivation and underactivation implicated. This study tested associations between sex-specific patterns of stress responses across the sympathetic nervous system (SNS) and hypothalamic–pituitary–adrenal (HPA) axis and peer nominations of aggression among 271 kindergarten children (Mean age = 5.32 years; 52% Female; 44% White). Upon entry to kindergarten, children participated in a multidomain standardized stress paradigm. Changes in pre-ejection period (PEP) and salivary cortisol were assessed. On a separate day, children provided peer ratings of physical and relational aggression in a standardized interview. As expected, there was a significant three-way interaction between PEP, cortisol reactivity, and sex, but only for physical aggression. Among boys, cortisol reactivity was positively associated with physical aggression only for those with higher SNS reactivity. Findings suggest that for boys, asymmetrical and symmetrical HPA/SNS reactivity may be associated with lower and higher risk for peer-directed physical aggression, respectively. Understanding the complex associations between multisystem physiology, child sex and peer-directed aggression in early childhood may offer insight into individual differences underlying the emergence of behavioral dysregulation in early peer contexts.


Author(s):  
Govind Kannan ◽  
Zaira M Estrada-Reyes ◽  
Phaneendra Batchu ◽  
Brou Kouakou ◽  
Thomas H Terrill ◽  
...  

Abstract Social isolation can increase distress in goats, particularly when they cannot maintain visual contact with conspecifics. This experiment was conducted to determine the behavioral and physiological responses in goats during isolation with or without visual contact with conspecifics. Male Spanish goats (uncastrated, 8-mo old, average weight 29.4 ± 0.59 kg) were randomly assigned to a control (CO) group with no isolation or to one of four isolation treatment (TRT) pens (1.5 × 1.5 m) with: (1) open grill panels but with no visual contact with conspecifics (IO), (2) covered grill to prevent visual contact (IC), (3) open grill with visual contact (IV), or (3) covered grill with a 30 × 30 cm window to allow visual contact (IW) for 90 min of social isolation (n = 12 goats/TRT). Blood samples were collected at 0, 30, 60, and 90 min (Time) from isolated and control goats. The experiment was repeated one week later using the same animals, with each goat being subjected to the same isolation treatment the second time to study the effect of prior exposure to isolation. Friedman’s Two-Way ANOVA by Ranks Test in SAS showed that the median frequency of vocalization (rank score) in goats was high in IO group, low in IV and IW groups, and intermediate in IC group (P < 0.01). Vocalization rank score was also higher (P < 0.01) during the first 30 min of isolation in goats. Median frequency of visual contact was higher in the IW group than in the IV group (P < 0.01). Frequency of climbing behavior was high in IC and IO groups, low in IV group, and intermediate in IW group (P < 0.01). Repeated Measures Analysis using GLM procedures in SAS revealed that plasma cortisol and glucose concentrations tended (P < 0.1) to be the highest in IO group than in CO, IC, IV, and IW groups. Cortisol levels were also higher (Time; P < 0.05) at 0 and 90 min compared to 30 and 60 min. Norepinephrine concentrations decreased (P < 0.05) with Time, and plasma non-esterified fatty acid (NEFA) levels were affected by TRT × Time interaction (P < 0.01). Overall, epinephrine, norepinephrine, glucose, and NEFA concentrations were lower (P < 0.01) and cortisol concentrations and lymphocyte counts higher (P < 0.01) when goats were exposed to isolation the second time. The results showed that goats with no visual contact with conspecifics during social isolation had greater physiological stress responses and spent more time vocalizing or trying to escape the pen, which may indicate distress.


2021 ◽  
pp. 026988112097233
Author(s):  
Richard J Xia ◽  
Thomas Chao ◽  
Divya Patel ◽  
Gillinder Bedi

Background: Aspects of the canonical stress response differ in stimulant, opioid, and alcohol users relative to controls, and dysregulated responses to stress may contribute to continued use of these drugs. Little prior research has focused on stress responses in regular cannabis smokers. We assessed responses to a standardized laboratory social stress assay (the Trier Social Stress Task; TSST) in regular cannabis smokers (CANs) compared with controls (CONs). Methods: Healthy, non-treatment-seeking adult CANs (⩾4×/week; smoking cannabis as usual) and demographically matched CONs completed the TSST. Outcome measures were subjective mood, heart rate, and salivary cortisol. Results: Nineteen CANs (1 female) and 20 CONs (2 female) participated; groups were matched on trauma exposure, sex, race, and age. CANs smoked cannabis 6.4 ± 1.1 days/week. Eight CANs and one CON smoked tobacco cigarettes daily. Overall, the TSST produced expected increases in anxiety, negative mood states, cortisol, and heart rate. CANs had blunted subjective response to stress relative to CONs, but they did not differ in physiological (cortisol and cardiovascular) stress responding. Conclusion: These results indicate that CANs have blunted mood responses to social stress, but normative physiological stress responding. Observed differences could be due to residual effects of cannabis, reluctance to endorse negative mood states, or to issues related to identifying (i.e., emotional identification) or feeling (i.e., interoception) stress-related affective states. Further research is warranted to characterize the mechanisms of these differences and assess implications for daily functioning and treatment outcomes.


1986 ◽  
Vol 65 (6) ◽  
pp. 1058-1069 ◽  
Author(s):  
J.A. MENCH ◽  
A. van TIENHOVEN ◽  
J.A. MARSH ◽  
C.C. McCORMICK ◽  
D.L. CUNNINGHAM ◽  
...  

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