nest predation
Recently Published Documents


TOTAL DOCUMENTS

736
(FIVE YEARS 90)

H-INDEX

70
(FIVE YEARS 3)

2021 ◽  
Author(s):  
Shilong Liu ◽  
Qiao Xie ◽  
Aiwu Jiang ◽  
Eben Goodale

Abstract Background Begging brings benefits and costs for nestling birds: it can indicate their needs to their parents, but it can also be a cue used by predators to find the nest. The costs, like many variables related to nest predation, can be specific to what kinds of predators are present and their auditory capabilities. These costs and benefits could also be affected by human noise, as noise could disrupt communication to parents and eavesdropping by predators, although human-produced noise might be easily ignored if predators can hear high-frequency components of the begging. We studied nest predation on a generalist bird, the Red-whiskered Bulbul Pycnonotus jocosus, in a tropical rainforest in which there are many kinds of nest predators, including birds, mammals and reptiles. Results In a total of 160 artificial nests, we broadcast recordings of begging nestlings, with and without traffic noise, at two volume levels. We hypothesized that playback would increase predation relative to a silent control, and that mixing in traffic noise with the begging would decrease predation, as the begging signal was masked. However, we hypothesized that some predators, particularly small mammals with sensitive high-frequency hearing, might ignore the traffic noise. We found that predation was lowest for the control treatment, and lower for treatments mixed with traffic noise than for those without it. Small mammals, however, showed an unexpected pattern, strongly avoiding the treatments with traffic noise. Conclusion Our results demonstrate the human-associated noise can disturb nest predators and influence which kinds of predators use begging to locate nests.


Author(s):  
Paulo Victor Resende dos Santos ◽  
Ingrid Pinheiro Paschoaletto ◽  
Lia Nahomi Kajiki ◽  
Mariana de-Carvalho ◽  
Samara de Albuquerque Teixeira

2021 ◽  
pp. 119858
Author(s):  
Ever Tallei ◽  
Luis Rivera ◽  
Alejandro Schaaf ◽  
Maila Scheffer ◽  
Natalia Politi

2021 ◽  
Vol 11 (19) ◽  
pp. 13101-13117
Author(s):  
Martin Sládeček ◽  
Kateřina Brynychová ◽  
Esmat Elhassan ◽  
Miroslav E. Šálek ◽  
Veronika Janatová ◽  
...  

2021 ◽  
Author(s):  
Martin Bulla ◽  
Christina Muck ◽  
Daniela Tritscher ◽  
Bart Kempenaers

Biparental care requires coordination between parents. Such coordination might prove difficult if opportunities to communicate are scarce, which might have led to the evolution of elaborate and noisy nest relief rituals in species facing a low risk of predation. However, whether such conspicuous rituals also evolved in species that avoid predation by relying on crypsis remains unclear. Here, we used a continuous monitoring system to describe nest relief behavior during incubation in an Arctic-breeding shorebird with passive nest defense, the semipalmated sandpiper (Calidris pusilla). We then explored whether nest relief behavior provides information about parental cooperation and predicts incubation effort. We found that incubating parents vocalized twice as much before the arrival of their partner than during other times of incubation. In 75% of nest reliefs, the incubating parent left the nest only after its partner had returned and initiated the nest relief. In these cases, exchanges were quick (25s, median) and shortened over the incubation period by 0.1 – 1.4s per day (95%CI), suggesting that parents became more synchronized. However, nest reliefs were not cryptic. In 90% of nest reliefs, at least one parent vocalized, and in 20% of nest reliefs, the incubating parent left the nest only after its returning partner called instantaneously. In 30% of cases, the returning parent initiated the nest relief with a call; in 39% of these cases, the incubating partner replied. If the partner replied, the next off-nest bout was 1 – 4hr (95%CI) longer than when the partner did not reply, which corresponds to an 8 – 45% increase. Our results indicate that incubating semipalmated sandpipers, which rely on crypsis to avoid nest predation, have quick but acoustically conspicuous nest reliefs. Our results also suggest that vocalizations during nest reliefs may be important for the division of parental duties.


2021 ◽  
Vol 75 (8) ◽  
Author(s):  
Tore Slagsvold ◽  
Karen L. Wiebe

Abstract Some birds cover their eggs with nest material when they leave to forage. It has been suggested that such egg-covering aids thermoregulation or prevents predation but here we present a new hypothesis, that secondary cavity-nesting species cover their eggs to prevent nest usurpation by other birds. When the bottom of the cavity is dark, as when eggs are covered by nest material, it may be difficult for a prospecting competitor to see whether a defending nest owner or a predator is hiding inside the cavity. Competitors may therefore hesitate to enter dark cavities. We filmed 21 great tit (Parus major) nests during the egg-laying period and found that the female spent bouts of highly variable length outside the nest box (range 0.3–250 min, n = 51), so prospecting small passerines would have difficulty predicting whether an aggressive tit owner was in the box or would soon return. We presented prospecting male pied flycatchers (Ficedula hypoleuca) with a dyad of boxes (n = 93), each containing a great tit nest but only one with visible eggs. Flycatchers hesitated more to enter a nest box with no visible tit eggs than a box with exposed eggs. This was most evident for nest boxes with dark versus light interior paint, supporting the idea that better interior illumination makes prospecting birds more confident about entering an unfamiliar cavity. The usurpation and predation hypotheses are not mutually exclusive because both competitors and small predators may hesitate to enter dark, enclosed spaces if visibility is low. Significance statement Some birds deposit a layer of material on top of the eggs when they leave the nest. Several hypotheses have been proposed for such egg covering, for example that it may insulate the eggs and reduce the risk of nest predation. We propose a new hypothesis, namely that secondary hole-nesting birds cover their eggs when they leave the nest to prevent usurpation of the cavity by other birds. Great tits that we filmed at the nest during the egg-laying period could be absent for long periods. To test the hypothesis, we presented male pied flycatchers, potential nest competitors, with a dyad of nest boxes, each containing a great tit nest but only one with visible tit eggs. In support of the prediction, prospecting flycatchers hesitated to enter dark cavities with dark floors relative to boxes with exposed, reflective eggs.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Annie E. Schmidt ◽  
Grant Ballard ◽  
Amélie Lescroël ◽  
Katie M. Dugger ◽  
Dennis Jongsomjit ◽  
...  

AbstractGroup-size variation is common in colonially breeding species, including seabirds, whose breeding colonies can vary in size by several orders of magnitude. Seabirds are some of the most threatened marine taxa and understanding the drivers of colony size variation is more important than ever. Reproductive success is an important demographic parameter that can impact colony size, and it varies in association with a number of factors, including nesting habitat quality. Within colonies, seabirds often aggregate into distinct groups or subcolonies that may vary in quality. We used data from two colonies of Adélie penguins 73 km apart on Ross Island, Antarctica, one large and one small to investigate (1) How subcolony habitat characteristics influence reproductive success and (2) How these relationships differ at a small (Cape Royds) and large (Cape Crozier) colony with different terrain characteristics. Subcolonies were characterized using terrain attributes (elevation, slope aspect, slope steepness, wind shelter, flow accumulation), as well group characteristics (area/size, perimeter-to-area ratio, and proximity to nest predators). Reproductive success was higher and less variable at the larger colony while subcolony characteristics explained more of the variance in reproductive success at the small colony. The most important variable influencing subcolony quality at both colonies was perimeter-to-area ratio, likely reflecting the importance of nest predation by south polar skuas along subcolony edges. The small colony contained a higher proportion of edge nests thus higher potential impact from skua nest predation. Stochastic environmental events may facilitate smaller colonies becoming “trapped” by nest predation: a rapid decline in the number of breeding individuals may increase the proportion of edge nests, leading to higher relative nest predation and hindering population recovery. Several terrain covariates were retained in the final models but which variables, the shapes of the relationships, and importance varied between colonies.


2021 ◽  
Vol 13 (15) ◽  
pp. 8138
Author(s):  
Michael Manton ◽  
Per Angelstam

Wet grassland degradation is a global issue that involves both altered land cover patterns and ecological processes, which affect the distribution and abundance of species. The sharp decline in European wader bird (Charadrii) populations is a good example. The aim of this study is to test the hypothesis that the anthropogenic developmental stage of wet grassland habitats and landscapes drives avian nest predator abundance, and thus the predation pressure on nests, which is a major cause of wader bird declines. Using a macroecological approach we selected six wet grassland landscapes representing a gradient in both grassland habitat development and breeding wader population status in four European countries (Belarus, Iceland, Lithuania and Sweden). We (1) mapped wader and avian predator assemblages in multiple wet grassland patches in each landscape, (2) used artificial nests to estimate the relative rate of egg predation, and (3) analyzed relationships between nest predation pressure, corvid nest predators versus raptors, nest loss and the stage of wet grassland habitat and landscape development. We found (1) inverse relationships between the abundance of corvids and waders, as well as between wet grassland developmental stage and waders, and (2) a positive correlation between the probability of nest loss and the density of corvid birds. In conclusion, we found a clear macroecological pattern linking habitat quality, wader populations, nest predators and nest predation. These linkages stress the importance of including nest predation as a factor limiting wader bird populations, and that corvid control or management may be useful management tools.


2021 ◽  
Vol 9 ◽  
Author(s):  
Bertille Mohring ◽  
Frédéric Angelier ◽  
Kim Jaatinen ◽  
Charline Parenteau ◽  
Markus Öst

Predation risk affects the costs and benefits of prey life-history decisions. Predation threat is often higher during reproduction, especially in conspicuous colonial breeders. Therefore, predation risk may increase the survival cost of breeding, and reduce parental investment. The impact of predation risk on avian parental investment decisions may be hormonally mediated by prolactin and corticosterone, making them ideal tools for studying the trade-offs involved. Prolactin is thought to promote parental care and commitment in birds. Corticosterone is involved in allostasis and may either mediate reduced parental investment (corticosterone-fitness hypothesis), or promote parental investment through a reallocation of resources (corticosterone-adaptation hypothesis). Here, we used these hormonal proxies of incubation commitment to examine the impact of predation risk on reproduction in common eiders (Somateria mollissima) breeding in the Baltic Sea. This eider population is subject to high but spatially and temporally variable predation pressure on adults (mainly by the white-tailed eagle Haliaeetus albicilla and introduced mammalian predators) and nests (by the adult predators and exclusive egg predators such as hooded crows Corvus cornix). We investigated baseline hormonal levels and hatching success as a function of individual quality attributes (breeding experience, female and duckling body condition), reproductive investment (clutch weight), and predation risk. We expected individuals nesting in riskier environments (i.e., on islands where predation on adults or nests is higher, or in less concealed nests) to reduce their parental investment in incubation, reflected in lower baseline prolactin levels and either higher (corticosterone-fitness hypothesis) or lower (corticosterone-adaptation hypothesis) baseline corticosterone levels. Contrary to our predictions, prolactin levels showed a positive correlation with nest predation risk. The unexpected positive relationship could result from the selective disappearance of low-quality females (presumably having low prolactin levels) from risky sites. Supporting this notion, female body condition and hatching success were positively correlated with predation risk on females, and baseline prolactin concentrations were positively correlated with duckling body condition, a proxy of maternal quality. In line with the corticosterone-adaptation hypothesis, baseline corticosterone levels increased with reproductive investment, and were negatively associated with nest predation risk. Hatching success was lower on islands where nest predation risk was higher, consistent with the idea of reduced reproductive investment under increased threat. Long-term individual-based studies are now needed to distinguish selection processes occurring at the population scale from individually plastic parental investment in relation to individual quality and variable predation risk.


Sign in / Sign up

Export Citation Format

Share Document