scholarly journals Territorial Movements of Black-throated Blue Warblers in a Landscape Fragmented by Forestry

The Auk ◽  
2001 ◽  
Vol 118 (2) ◽  
pp. 544-549 ◽  
Author(s):  
Rebecca J. Harris ◽  
J. Michael Reed
Keyword(s):  
Bird Species ◽  
Small Scale ◽  
Neotropical Migrant ◽  
Dendroica Caerulescens ◽  
Alarm Calling ◽  
Second Year ◽  
Simulated Territorial Intrusion ◽  
Territorial Intrusion ◽  
Song Playback ◽  
Older Males

Abstract Many forest bird species show inhibition to entering open areas, including crossing habitat gaps. We examined the responses of Black-throated Blue Warblers (Dendroica caerulescens) to conspecific song playback within forest, at clearcut-forest ecotones, and across logging roads to assess movements of this Neotropical migrant into open areas. Males responded readily to song playbacks in all areas, and moved significantly farther into clearcuts than they did within intact forest (40.4 ± 2.9 m and 17.1 ± 1.2 m, respectively). Their singing, aggressive trilling, and alarm-calling rates were highest in response to playback from clearcuts, intermediate during road-crossings, and lowest within forest. Males moved farthest into the oldest regenerating clearcuts (>15 years old), indicating that vegetation structure also influences their movement into open areas. Second-year males were more responsive than older males, moving farther to reach speakers in all areas, and showing a nonsignificant trend of moving farther into clearcuts. We found that extensive movements into open areas occur in response to simulated territorial intrusion, indicating that small-scale habitat fragmentation by forestry may not disrupt territorial movements of that species.

scholarly journals Male White-shouldered Fairywrens (Malurus alboscapulatus) elevate testosterone when courting females but not during territorial challenges

2021 ◽  
Author(s):  
Jordan Boersma ◽  
John Anothny Jones ◽  
Erik D Enbody ◽  
Joseph F Welklin ◽  
Serena Ketaloya ◽  
...  
Keyword(s):  
Bird Species ◽  
Plasma Testosterone ◽  
Network Approach ◽  
Challenge Hypothesis ◽  
Agonistic Interactions ◽  
Causal Factors ◽  
Behavioral Traits ◽  
Social Network Approach ◽  
Simulated Territorial Intrusion ◽  
Territorial Intrusion

Testosterone mediates suites of physical and behavioral traits across vertebrates, and circulation varies considerably across and within taxa. However, an understanding of the causal factors of variation in circulating testosterone has proven difficult despite decades of research. According to the challenge hypothesis, agonistic interactions between males immediately prior to the breeding season produce the highest levels of testosterone measured during this period. While many studies have provided support for this hypothesis, most species do not respond to male-male competition by elevating testosterone. As a result, a recent revision of the hypothesis (challenge hypothesis 2.0) places male-female interactions as the primary cause of rapid elevations in testosterone circulation in male vertebrates. Here, we offer a test of both iterations of the challenge hypothesis in a tropical bird species. We first illustrate that male White-shouldered Fairywrens (Malurus alboscapulatus) differ by subspecies in plasma testosterone concentrations. Then we use a social network approach to find that males of the subspecies with higher testosterone are characterized by greater social interaction scores, including more time aggregating to perform sexual displays. Next, we use a controlled experiment to test whether males respond to simulated territorial intrusion or courtship interaction contexts by elevating testosterone. Males sampled during courtship had greater plasma testosterone both relative to flushed controls and males sampled during simulated intrusion. Ultimately, our results are consistent with challenge hypothesis 2.0, as males rapidly elevated testosterone following interactions with females, but not during territorial challenges.

scholarly journals Defending as a unit: sex- and context-specific territorial defence in a duetting bird

2020 ◽  
Author(s):  
Lucia Mentesana ◽  
Maria Moiron ◽  
Ernesto Guedes ◽  
Enzo Cavalli ◽  
Bettina Tassino ◽  
...  
Keyword(s):  
Structural Equation Modelling ◽  
Latent Variable ◽  
Structural Equation ◽  
Bird Species ◽  
Correlation Pattern ◽  
Territorial Defence ◽  
Equation Modelling ◽  
Simulated Territorial Intrusion ◽  
Territorial Intrusion ◽  
Context Specific

AbstractBehaviours such as territorial defence represent functionally integrated traits that underlie multiple behavioural variables such as physical and acoustic responses. Characterizing the multivariate structure of such traits is fundamental to understand their evolution. In bird species that form stable pair bonds and are territorial year-round, both sexes are expected to defend their territory; however, the role that each sex plays in defending their shared territory remains largely unknown. Evidence for the sex-roles during territorial defence is mixed and sex- and context-specific characterizations of territorial defence embracing the multivariate nature of the trait are currently lacking. Here we investigated sex- and context-specific variation in a hypothesised latent variable called “territorial defence” and tested whether duets were part of territorial defence in a wild population of rufous hornero (Furnarius rufus). To do so, we combined a simulated territorial intrusion approach during nest building and provisioning contexts with a structural equation modelling approach. Our results showed that, in males and females, the six measured behavioural variables were linked by a single latent trait, territorial defence, in both contexts. Flights over the decoy and duet songs were equally good proxies of territorial defence. Although males were defending more the territory than females, pair members showed a positive correlation in their behaviour. The structural equation modelling framework enabled us to capture a complex correlation pattern among behavioural variables, expanding upon a classic body of research on territorial defence. Thus, the combination of classical behavioural approaches with sophisticated statistical analyses brings new exciting possibilities to the field of behavioural ecology.Significance statementTerritorial defence is a key behaviour in territorial species as it plays a major role in an individual’s reproductive success and survival. Additionally, territorial defence has been proposed as one possible evolutionary driver of duetting behaviour, one of the most fascinating vocal behaviours in birds. As behaviours are evolutionary characters, they must be studied in a multivariate framework. In this study we focused on characterizing territorial defence during a simulated territorial intrusion in an integrative manner using a classical territorial intrusion framework. We did so in male and female rufous horneros (Aves: Furnaridae) across two breeding contexts, while simultaneously testing theoretical predictions about the role of duetting behaviour as key part of territorial defence. Overall, our study provides for the first time a sex- and context-comparison of the multivariate, latent variable “territorial defence” in duetting birds, while highlighting the potential of combining field behavioural approaches with structural equation modelling.

Effects of forest–clearcut edges on a forest-breeding songbird

2002 ◽  
Vol 80 (6) ◽  
pp. 1026-1037 ◽  
Author(s):  
Rebecca J Harris ◽  
J Michael Reed
Keyword(s):  
Reproductive Success ◽  
Food Source ◽  
Forest Landscape ◽  
Resource Abundance ◽  
Neotropical Migrant ◽  
Dendroica Caerulescens ◽  
Forestry Practices ◽  
Forest Sites ◽  
Interior Forest ◽  
Negative Impacts

To understand local and regional changes in Neotropical migrant songbird populations it is important to determine whether forest-breeders can use and persist in the dynamic, variegated landscapes created by modern forestry practices. We made detailed observations of a species classified as a mature-forest specialist, the black-throated blue warbler (Dendroica caerulescens), adjacent to clearcut edges and in intact forest in a large industrial forest landscape. We measured reproductive success, habitat use, resource abundance, the potential for inter- and intra-specific competition, and predator densities. Unlike most studies of edge effects, our study showed both positive and negative impacts of associations with edges. We recorded a lower density of potential avian competitors within intact forest, as well as a higher proportion of older male black-throated blue warblers at interior forest sites. In addition, proportionally more fledglings were observed in intact forest. However, males at edge sites had higher pairing success and edges had higher understory density (which is positively associated with reproductive success in other studies), evidence of higher abundance of their primary food source and lower densities of diurnal egg and nestling predators. The net result of these mixed patterns is that males gaining a territory at edge or interior sites appeared to have similar probabilities of producing fledglings.

The emergence of tolerance of human disturbance in Neotropical birds

2019 ◽  
Vol 36 (1) ◽  
pp. 1-5 ◽  
Author(s):  
Piotr Tryjanowski ◽  
Jakub Z. Kosicki ◽  
Martin Hromada ◽  
Peter Mikula
Keyword(s):  
North America ◽  
Human Disturbance ◽  
Escape Response ◽  
Bird Species ◽  
Small Scale ◽  
Behavioural Plasticity ◽  
Mato Grosso ◽  
Animal Populations ◽  
History Of ◽  
Rapid Emergence

AbstractAnimals living close to human settlements more often experience disturbance, but also reduced predation risk. Because an escape response is costly, behavioural adjustments of animals in terms of increased tolerance of humans occurs and is often reported in the literature. However, most such studies have been conducted in and around long-existing cities in Europe and North America, on well-established animal populations. Here, we investigate the degree of tolerance of human disturbance across 132 bird species occurring in disturbed (small farms) and undisturbed (intact wetlands and grasslands) areas in Pantanal, Mato Grosso (Brazil), a region with only a very recent history of human-induced disturbance. We found a clear across-species trend toward higher tolerance of human disturbance in birds near farms when compared with birds in wild areas. Such a flexible and perhaps also rapid emergence of tolerance when facing small-scale and very recent human disturbance presumably involves learning and might be attributed to behavioural plasticity. The ability of birds to modify their degree of tolerance of human disturbance may play a key role in the facilitation of wildlife–human coexistence.

scholarly journals Robert Abbott Hadfield, 1858 - 1940

1941 ◽  
Vol 3 (10) ◽  
pp. 647-664 ◽  
Keyword(s):  
Small Scale ◽  
General Belief ◽  
Interest In Science ◽  
Great Saving ◽  
International Exhibitions ◽  
Steel Castings ◽  
Hydraulic Cylinders ◽  
Second Year ◽  
Set Up ◽  
Steel Projectiles

Robert Abbott Hadfield, head of the great steel firm bearing his name, died at his house on Kingston Hill on 30 September 1940, in his eighty-second year. He was born at Attercliffe, then still a village, on 28 November 1858, and came of a Derbyshire family which had long been connected with Sheffield. His father, Robert Hadfield, who had gained experience in several branches of the steel industry, at that time carried on on a small scale, in 1872 set up a works with the special object of making steel castings, then a novelty in this country, although practised on the Continent. The enterprise was considered rather rash, on account of a general belief that steel must be forged before it could acquire such mechanical properties as to make it a trustworthy material, but it proved very successful, and the castings, which included such large objects as hydraulic cylinders, showing a great saving of weight over cast iron, gained medals at several international exhibitions. The firm also produced steel projectiles, which until then had only been manufactured in France. Robert Hadfield declined to buy foreign patents for these, and developed their production independently, thus laying the foundation of what was to become one of the leading armament firms. His son attended the Collegiate School in Sheffield, and was taught chemistry by William Baker, whose lecture demonstrations seem to have attracted him. His interest in science was stimulated by reading Pepper’s Playbook of Science and Playbook of Metals , two excellent books which must have influenced the careers of many boys.

scholarly journals Predicting continental-scale patterns of bird species richness with spatially explicit models

2006 ◽  
Vol 274 (1607) ◽  
pp. 165-174 ◽  
Author(s):  
Carsten Rahbek ◽  
Nicholas J Gotelli ◽  
Robert K Colwell ◽  
Gary L Entsminger ◽  
Thiago Fernando L.V.B Rangel ◽  
...  
Keyword(s):  
Species Richness ◽  
Bird Species ◽  
Small Scale ◽  
Spatially Explicit ◽  
Bird Species Richness ◽  
Continental Scale ◽  
Historical Factors ◽  
Biotic Diversity ◽  
Correlative Models ◽  
Richness Patterns

The causes of global variation in species richness have been debated for nearly two centuries with no clear resolution in sight. Competing hypotheses have typically been evaluated with correlative models that do not explicitly incorporate the mechanisms responsible for biotic diversity gradients. Here, we employ a fundamentally different approach that uses spatially explicit Monte Carlo models of the placement of cohesive geographical ranges in an environmentally heterogeneous landscape. These models predict species richness of endemic South American birds (2248 species) measured at a continental scale. We demonstrate that the principal single-factor and composite (species-energy, water-energy and temperature-kinetics) models proposed thus far fail to predict ( r 2 ⩽0.05) the richness of species with small to moderately large geographical ranges (first three range-size quartiles). These species constitute the bulk of the avifauna and are primary targets for conservation. Climate-driven models performed reasonably well only for species with the largest geographical ranges (fourth quartile) when range cohesion was enforced. Our analyses suggest that present models inadequately explain the extraordinary diversity of avian species in the montane tropics, the most species-rich region on Earth. Our findings imply that correlative climatic models substantially underestimate the importance of historical factors and small-scale niche-driven assembly processes in shaping contemporary species-richness patterns.

Opposite Changes in Plasma Testosterone and Corticosterone Levels Following a Simulated Territorial Challenge in Male Great Tits

Behaviour ◽  
2004 ◽  
Vol 141 (4) ◽  
pp. 451-467 ◽  
Author(s):  
Rianne Pinxten ◽  
Lutgarde Arckens ◽  
Els van Duyse ◽  
Marcel Eens ◽  
Veerle Darras
Keyword(s):  
Parus Major ◽  
Time Of Day ◽  
Behavioural Response ◽  
Egg Laying ◽  
Plasma Testosterone ◽  
Breeding Cycle ◽  
Territorial Defence ◽  
Breeding Stage ◽  
Simulated Territorial Intrusion ◽  
Territorial Intrusion

AbstractThe apparent ability of plasma testosterone (T) and corticosterone (B) levels to fluctuate rapidly in response to agonistic interactions, suggests that these hormones may play an important role in an animal's acute behavioural response during such interactions. In the present study, free-living male great tits, Parus major, were subjected to a simulated territorial intrusion (STI) during the egg laying, incubation and nestling stage of first broods. Plasma T and B levels of challenged males were compared to those of control males matched for breeding stage, day in breeding stage, and time of day. Plasma B levels were significantly higher in challenged males compared to control males during the egg laying and incubation stage but not during the nestling stage. On the other hand, challenged males had significantly lower plasma T levels than control males throughout the breeding cycle. While having low plasma T and elevated plasma B levels, challenged males showed a vigorous and unrelenting territorial response to the STI. Plasma T and B levels of challenged males did not correlate with the intensity of the behavioural response to the STI. These findings do not agree with the predictions of the 'challenge hypothesis' that males exposed to a territorial challenge while having breeding baseline T levels will respond with an increase in T or that T correlates with the intensity of aggression during a challenge. Together, our findings suggest a role for B rather than T in the regulation of territorial defence in male great tits.

Use of Stereo Duet Playback to Investigate Traditional Duet Playback Methods and Mechanisms of Cooperative Territorial Defence in Magpie-Larks

Behaviour ◽  
2004 ◽  
Vol 141 (6) ◽  
pp. 741-753 ◽  
Author(s):  
Helèna Harrington ◽  
Audrey Miller ◽  
Sarah Mcdowell ◽  
Amy Rogers ◽  
Joanne Panagos ◽  
...  
Keyword(s):  
Intraspecific Aggression ◽  
Same Sex ◽  
Territorial Defence ◽  
Male And Female ◽  
Single Speaker ◽  
Simulated Territorial Intrusion ◽  
Territorial Intrusion ◽  
Australian Magpie ◽  
Response Variables

AbstractDuets are precisely coordinated acoustic displays, usually involving members of a mated pair. Studies investigating avian duet function often employ a single speaker playback system to compare response of focal pairs to simulated territorial intrusion by duetting and solo birds. It has recently been suggested that a 'stereo duet playback', in which male and female duet components are separated and broadcast through two different speakers, would provide a more realistic duet stimulus. We conduct the first comparison of a traditional single speaker versus a new stereo duet playback design and provide evidence that Australian magpie-larks, Grallina cyanoleuca, make significantly more flights towards duet playback presented in a more realistic stereo context. Male and female magpie-lark pairs did not split up and attack one 'intruder' each when presented with a stereo duet playback. Instead they moved towards the same speaker together as a united pair, showing a tendency to approach the speaker initiating the duet intrusion. Distance between the two speakers in a stereo duet design did not have a significant effect on the response variables measured. We conclude that magpie-larks can distinguish between use of a single speaker or stereo duet playback to broadcast a duet and suggest that cooperative defence against duetting intruders in magpie-larks is a result of joint territorial defence rather than intraspecific aggression against same-sex intruders.

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