scholarly journals Plastering mud around the entrance hole affects the estimation of threat levels from nest predators in Eurasian Nuthatches

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Jiangping Yu ◽  
Li Zhang ◽  
Guodong Yi ◽  
Keqin Zhang ◽  
Jiyuan Yao ◽  
...  
Keyword(s):  
Nest Defence ◽  
Hole Size ◽  
Red Squirrels ◽  
Cavity Nesting ◽  
Sitta Europaea ◽  
Entrance Hole ◽  
Tamias Sibiricus ◽  
Threat Levels ◽  
Nest Predator ◽  
Nest Predators

Abstract Background For cavity-nesting birds, the nest entrance plays an important role in preventing predators from accessing nests. Several species of nuthatches use mud to narrow the entrance of cavities. In theory, the smaller the entrance hole size, the more effective it is against predators; however, few studies have tested whether narrowing the entrance hole size can affect the estimation of threat levels from nest predators in cavity-nesting birds. Methods Using dummy experiments, we tested whether Eurasian Nuthatches (Sitta europaea, narrow the entrance hole of cavities) and Cinereous Tits (Parus cinereus, do not narrow the entrance hole, as a control) perform different nest defence behaviours against Common Chipmunks (Tamias sibiricus, small nest predator) and Red Squirrels (Sciurus vulgaris, larger nest predator). Results Both nuthatches and tits exhibited stronger response behaviours (high dummy response scores) against chipmunks than against squirrels. Compared with tits, nuthatches exhibited more aggressive behaviours to chipmunks, but their responses to squirrels were similar. Conclusions Nest defence behaviours of nuthatches to chipmunks differed from tits, and the results suggested that nuthatches might estimate threat levels of nest predators according to their narrowed entrance-hole size.

Does the intrusion of an avian nest predator elicit a change in the behaviour of a canopy-nesting passerine?

Behaviour ◽  
2021 ◽  
pp. 1-26
Author(s):  
Alexander R. Sharp ◽  
Kamal Islam
Keyword(s):  
Nest Defence ◽  
Cyanocitta Cristata ◽  
Potential Predator ◽  
Reduce Activity ◽  
Provisioning Rate ◽  
Avian Nest ◽  
Cerulean Warblers ◽  
Stage 1 ◽  
Nest Predator ◽  
Nest Predators

Abstract Many studies have shown that nest predators affect their prey indirectly by inducing changes in the behaviour of the prey. Studies suggest that the type and degree of nest defence strategies depends heavily on species, along with nest type and location. One such strategy, nest vigilance, allows individuals to collect information and make informed decisions based on their surroundings. In this study, we simulated the intrusion of a common avian nest predator (blue jay, Cyanocitta cristata) into the territory of nesting cerulean warblers (Setophaga cerulea) and evaluated eight different behavioural variables to determine their response to the nest predator. Female cerulean warblers were more vigilant on their nest when exposed to a potential predator compared to a nest with lower threat of predation. Females exposed to a nest predator increased incubation bout by 109% and brooding bout by 60%. Our data also suggest that male cerulean warblers reduce their provisioning rate during the early nestling stage (−1 feeding/hour) and late nestling stage (−3 feedings/hour), although more data are needed. Modification of incubation bout length and nestling provisioning rate are common strategies employed by songbirds to reduce activity around the nest, by decreasing detection opportunities of visually-oriented nest predators. Currently, the only understanding we have on how cerulean warblers respond to a nest predator is based on observational data. The results of this study provide the first evidence that cerulean warblers are able to identify species that pose a threat to the safety of their nest, and that they modify their behaviour to reduce nest detection by predators. The results of this study provide a better understanding of a relatively unknown aspect of the breeding behaviour of this species. This study is also first to describe how an open-cup, canopy-nesting species responds to an increase in nest predation threat.

Tests of two functions of alarm calls given by yellow warblers during nest defence

2003 ◽  
Vol 81 (10) ◽  
pp. 1685-1690 ◽  
Author(s):  
Sharon A Gill ◽  
Spencer G Sealy
Keyword(s):  
Molothrus Ater ◽  
Egg Laying ◽  
Nest Defence ◽  
Alarm Calls ◽  
Potential Danger ◽  
Dendroica Petechia ◽  
Yellow Warblers ◽  
Avian Nest ◽  
Nest Predators

During nest defence, yellow warblers (Dendroica petechia) give "seet" and "chip" calls. Seet calls are given preferentially toward brood parasitic brown-headed cowbirds (Molothrus ater) during the yellow warblers' egg-laying period, whereas chip calls are given toward mammalian and avian nest predators throughout the nesting period. In this study, we investigated two possible functions of seet and chip calls during nest defence by playing alarm calls to nesting yellow warblers. We tested whether nest owners give seet and chip calls during defence to alert their offspring and their mates about nest threats and, in the latter case, whether the alarm calls differ in function depending on nesting stage. In response to playbacks, nestlings remained inactive for a significantly longer period when chip calls were played than when seet calls were played. Female yellow warblers returned to their nesting areas more quickly when seet calls were played than when chip calls were played, but pairs were equally likely to return to the nesting area in response to both call types. These findings suggests that both seet and chip calls alert mates but that only chip calls function to alert nestlings of potential danger.

Nest Box Entrance Hole Size Influences Prey Delivery Success by American Kestrels

2020 ◽  
Vol 54 (3) ◽  
Author(s):  
Logan B. Clark ◽  
Megan E. Shave ◽  
Melissa B. Hannay ◽  
Catherine A. Lindell
Keyword(s):  
Hole Size ◽  
Nest Box ◽  
American Kestrels ◽  
Entrance Hole

scholarly journals Differently sized cuckoos pose different threats to hosts

2019 ◽  
Vol 66 (3) ◽  
pp. 247-253 ◽  
Author(s):  
Jiangping Yu ◽  
Mingju E ◽  
Wei Sun ◽  
Wei Liang ◽  
Haitao Wang ◽  
...  
Keyword(s):  
Size Variation ◽  
Alarm Calls ◽  
Playback Experiments ◽  
Egg Ejection ◽  
Local Diversity ◽  
Ejection Rate ◽  
Threat Level ◽  
Streptopelia Orientalis ◽  
Tamias Sibiricus ◽  
Nest Predator

Abstract Hole-nesting tits Parus spp. have been classified as “unsuitable” hosts for cuckoo parasitism because cuckoos cannot enter a cavity if the entrance is too small. However, Chinese tits could reject alien eggs and egg ejection rate increased with the local diversity of parasitic cuckoo species. Antiparasitic behavior among Chinese tits may have evolved due to greater size variation among sympatric cuckoo species. This raises the question of whether differently sized parasitic cuckoos pose different threats to Chinese tits. A green-backed tit Parus monticolus population that is sympatric with Asian emerald cuckoo Chrysococcyx maculatus (eme-cuckoo, small-sized parasite) and common cuckoo Cuculus canorus (com-cuckoo, large-sized parasite), and a cinereous tit P. cinereus population that is only sympatric with com-cuckoo were chosen as study organisms. We observed behavioral response and recorded alarm calls of the 2 tit species to eme-cuckoo, com-cuckoo, chipmunk Tamias sibiricus (a nest predator) and dove Streptopelia orientalis (a harmless control), and subsequently played back alarm calls to conspecific incubating females. In dummy experiments, both tit species performed intense response behavior to chipmunk, but rarely responded strongly to the 3 avian species. In playback experiments, both tit species responded strongly to conspecific chipmunk alarm calls, but rarely responded to dove alarm calls. The intensity of response of incubating female green-backed tits to eme-cuckoo and com-cuckoo alarm calls were similar to that of chipmunk alarm calls, while the intensity to eme-cuckoo alarm calls was higher than the intensity to dove alarm calls which was similar to that of com-cuckoo alarm calls. In contrast, few female cinereous tits responded to eme-cuckoo and com-cuckoo alarm calls. These findings indicated that the threat level of eme-cuckoo was slightly greater than that of com-cuckoo for sympatric green-backed tits, but not for allopatric cinereous tits.

Response to logging by a limited but variable nest predator guild in the boreal forest

2008 ◽  
Vol 38 (7) ◽  
pp. 1974-1982 ◽  
Author(s):  
Randy G. Thompson ◽  
Ian G. Warkentin ◽  
Stephen P. Flemming
Keyword(s):  
Boreal Forest ◽  
Nest Predation ◽  
Forest Cover ◽  
Landscape Fragmentation ◽  
Artificial Nests ◽  
Gray Jays ◽  
Predator Guild ◽  
Nest Predator ◽  
Predation Rates ◽  
Nest Predators

Predation rates on the eggs and young of forest-nesting songbirds typically rise in association with anthropogenic fragmentation, but predator responses depend on the spatial scale of disturbance, context, and predator assemblages present. For landscapes that are naturally fragmented, such as the boreal forest, our understanding of nest predation patterns associated with harvest may be further confounded by an additive response of nest predators to the loss of forest cover and the extension of habitat edges. We examined predation rates on artificial nests across a range of values for landscape metrics reflecting natural and anthropogenic forest fragmentation during two summers in boreal forest stands of western Newfoundland, Canada. Nest predation by gray jays ( Perisoreus canadensis (L.)) increased significantly in logged areas, and gray jay abundance was positively linked to increasing amounts of logged edge; however, there was no response to the extent of natural openings suggesting that nest predation by jays was additive in the presence of harvest-created openings. In contrast, neither mammalian nest predators nor the unidentified predators (responsible for the largest proportion of nest losses) showed any association with the landscape fragmentation metrics assessed. Year effects shown by the unidentified nest predator category did coincide with a marked increase in small mammal and Newfoundland marten ( Martes americana (Turton) subsp. atrata (Bangs)) populations during our study. Thus, we were able to identify an additive predation response to logging, but also that the activities of predators may vary over space and time and, in turn, may variably influence the success of songbirds nesting in forests fragmented by logging.

scholarly journals Partner abundance controls mutualism stability and the pace of morphological change over geologic time

2017 ◽  
Vol 114 (15) ◽  
pp. 3951-3956 ◽  
Author(s):  
Guillaume Chomicki ◽  
Susanne S. Renner
Keyword(s):  
Morphological Change ◽  
Theoretical Models ◽  
Stabilizing Selection ◽  
Hole Size ◽  
Rates Of Evolution ◽  
Entrance Hole ◽  
Mutualism Stability ◽  
Related Trait ◽  
Different Levels ◽  
Mutualism Breakdown

Mutualisms that involve symbioses among specialized partners may be more stable than mutualisms among generalists, and theoretical models predict that in many mutualisms, partners exert reciprocal stabilizing selection on traits directly involved in the interaction. A corollary is that mutualism breakdown should increase morphological rates of evolution. We here use the largest ant-plant clade (Hydnophytinae), with different levels of specialization for mutualistic ant symbionts, to study the ecological context of mutualism breakdown and the response of a key symbiosis-related trait, domatium entrance hole size, which filters symbionts by size. Our analyses support three predictions from mutualism theory. First, all 12 losses apparently only occur from a generalist symbiotic state. Second, mutualism losses occurred where symbionts are scarce, in our system at high altitudes. Third, domatium entrance hole size barely changes in specialized symbiotic species, but evolves rapidly once symbiosis with ants has broken down, with a “morphorate map” revealing that hotspots of entrance hole evolution are clustered in high-altitude areas. Our study reveals that mutualistic strategy profoundly affects the pace of morphological change in traits involved in the interaction and suggests that shifts in partners’ relative abundances may frequently drive reversions of generalist mutualisms to autonomy.

Nest Defence By Yellow Warblers: Recognition of a Brood Parasite and an Avian Nest Predator

Behaviour ◽  
1996 ◽  
Vol 133 (3-4) ◽  
pp. 263-282 ◽  
Author(s):  
Sharon A. Gill ◽  
Spencer G. Sealy
Keyword(s):  
Brood Parasitism ◽  
Nest Defence ◽  
Brood Parasite ◽  
Yellow Warbler ◽  
Nest Protection ◽  
Yellow Warblers ◽  
Avian Nest ◽  
Defensive Behaviours ◽  
And Control ◽  
Nest Predator

AbstractYellow warblers (Dendroica petechia) were exposed to taxidermic mounts of a brood parasite (brown-headed cowbird, Molothrus ater), avian nest predator (common grackle, Quiscalus quiscula) and control (fox sparrow, Passerella iliaca) during their laying and nestling stages to determine whether nest owners distinguish between the threats of brood parasitism and predation. Yellow warblers responded more intensely to the cowbird at the laying stage, performing two unique behaviours (seet calling and nest-protection behaviour) in response to this threat. By contrast, yellow warbler responses to the grackle were greater at the nestling stage, consisting largely of alarm calls (chip, metallic chip and warble calls). The sparrow model infrequently elicited aggressive behaviour from nest owners at either stage. These responses support the hypothesis that yellow warblers discriminate between threats of brood parasitism and nest predation. Yellow warblers may perform specific behaviours to cowbirds because defensive behaviours used against predators may be incompatible with cowbird deterrence. Female nest owners responded more frequently than males at the laying stage, and more intensely than males at both nesting stages. The distance that females and males approached the models and several aggressive behaviours were positively correlated. The greater responsiveness of females may be because they dominate their mates and because females are more experienced with intruders near the nest.

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