scholarly journals Egg covering in cavity nesting birds may prevent nest usurpation by other species

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 8 (11) ◽  
Author(s):  
Tore Slagsvold ◽  
Karen L. Wiebe

Many species of birds incorporate feathers into their nest as structural support and to insulate the eggs or offspring. Here, we investigated the novel idea that birds reduce the risk of nest usurpation by decorating it with feathers to trigger a fear response in their rivals. We let prospecting birds choose between a dyad of nest-boxes in the wild, both containing some nest materials, but where one had a few white feathers and the other had none. All three species of cavity-nesting birds studied, the pied flycatcher Ficedula hypoleuca , the blue tit Cyanistes caeruleus , and the tree swallow Tachycineta bicolor , hesitated to enter boxes with white feathers. A similar avoidance of white feathers was found when the alternative nest-box of a dyad held black feathers. However, the birds readily collected white feathers that we placed in front of their nest-box, showing the fear of such feathers was context-dependent. We suggest that naive prospecting birds may perceive feathers in nests as the result of a predation event, and that owners decorate nests with bright feathers that can be seen from the opening to deter others from entering.


2020 ◽  
Author(s):  
Melanie Lindner ◽  
Veronika N. Laine ◽  
Irene Verhagen ◽  
Heidi M. Viitaniemi ◽  
Marcel E. Visser ◽  
...  

ABSTRACTClimate change significantly impacts natural populations, particularly phenology traits, like the seasonal onset of reproduction in birds. This impact is mainly via plastic responses in phenology traits to changes in the environment, but the molecular mechanism mediating this plasticity remains elusive. Epigenetic modifications can mediate plasticity and consequently constitute promising candidates for mediating phenology traits. Here, we used genome-wide DNA methylation profiles of individual great tit (Parus major) females that we blood sampled repeatedly throughout the breeding season. We demonstrate rapid and directional variation in DNA methylation within the regulatory region of genes known to play key roles in avian reproduction that are in line with observed changes in gene expression in chickens. Our findings provide an important step towards unraveling the molecular mechanism mediating a key life history trait, an essential knowledge-gap for understanding how natural populations may cope with future climate change.IMPACT SUMMARYNatural populations are increasingly challenged by changing environmental conditions like global increases in temperature. A key way for species to adapt to global warming is via phenotypic plasticity, i.e. the ability to adjust the expression of traits to the environment. We, however, know little about how the environment can interact with an organism’s genetic make-up to shape its trait value. Epigenetic marks are known to vary with the environment and can modulate the expression of traits without any change in the genetic make-up and therefore have the potential to mediate phenotypic plasticity.To study the role of epigenetics for phenotypic plasticity, we here focus on the great tit (Parus major), a species that is strongly affected by global warming and plastic for temperature in an essential phenology trait, the seasonal onset of egg laying. As a first step, we investigated whether great tit females show within-individual and short-term variation in DNA methylation that corresponds to changes in the reproductive state of females. We therefore housed breeding pairs in climate-controlled aviaries to blood sample each female repeatedly throughout the breeding season and used these repeated samples for methylation profiling.We found rapid and directional variation in DNA methylation at the time females prepared to initiate egg laying that is located within the regulatory region of genes that have previously described functions for avian reproduction. Although future work is needed to establish a causal link between the observed temporal variation in DNA methylation and the onset of reproduction in female great tits, our work highlights the potential role for epigenetic modifications in mediating an essential phenology trait that is sensitive to temperatures.


The Auk ◽  
2004 ◽  
Vol 121 (1) ◽  
pp. 184-191 ◽  
Author(s):  
Leen Gorissen ◽  
Marcel Eens

Abstract Studies of the dawn chorus in birds have focused mainly on the behavior and song output of males and on the function(s) of male song. Less attention has been paid to the females' behavior and to communication between members of a pair. In Great Tits (Parus major), males sing vigorously at dawn in the vicinity of the female's nest hole just before and during egg laying. We studied the female's vocal behavior during the dawn chorus as well as communication between pair members. All females vocally interacted with their mates from inside the nest box. Females produced a sound with a very low sound-pressure level only audible from few meters, which we have named the “quiet call.” This quiet call was unique to females and was only produced from inside the nest box. To our knowledge, our study is the first to show that both members of a pair vocally interact during the dawn chorus. Given that many temperate-zone bird species have similar life histories as the Great Tit, it is very likely that similar interactive behavior occurs in other (song)birds. This interactive behavior may provide a new and manipulable tool for testing hypotheses about the dawn song and can be used as a future bioassay of male vocalizations.


2019 ◽  
Vol 80 (2) ◽  
pp. 137-143
Author(s):  
Grzegorz Zawadzki ◽  
Jerzy Zawadzki ◽  
Dorota Zawadzka ◽  
Anna Sołtys

Abstract In 2011–2014, the occupancy of nest-boxes by secondary hole-nesting birds and their breeding success was investigated in pine stands of the Augustów Forest (North-Eastern Poland). In the studied area of 12600 ha, the share of Scots Pine Pinus sylvestris L. in the stands was 92%. On average, birds occupied 54% and bats 3% of the 224–317 nest boxes controlled yearly. Nest boxes were also used by the Pygmy Owl Glaucidium passerinum L. as food caches. In total, broods of nine secondary hole-nesting species were observed, but only four bird species nested in each year of study. The most numerous species, occupying 53–60% of all boxes each year was the Pied Flycatcher Ficedula hypoleuca Pall. The Great Tit Parus major L. occupied 15–24% and the Coal Tit Periparus ater L. 10–12% of available nest-boxes, while the Redstart Phoenicurus phoenicurus L. used 2–7% of nest boxes. The yearly breeding success was highest for tits (Great Tit – 52–84%, Coal Tit – 50–72%) and strongly variable for the Pied Flycatchers – 38–78%. Broods were lost due to predation by martens Martes sp. (38%) and great spotted woodpeckers Dendrocopos major L. (6%) as well as nest competition (2%). The nest-boxes were occupied at a constant rate during the following four years after their exposition. Over 67% of the new nest-boxes were occupied annually which means new nest-boxes (up to 4 years) were occupied significantly more often than boxes older than 4 years.


Author(s):  
Catherine Dale ◽  
Matthew W Reudink ◽  
Laurene M Ratcliffe ◽  
Ann E McKellar

Artificial nest boxes provide an important resource for secondary cavity-nesting passerines, whose populations may be limited by the availability of nesting sites. However, previous studies have demonstrated that the design and placement of boxes may affect the reproductive success of the birds that use them. In this study, we asked whether the habitat surrounding a nest box or the type of box influenced reproduction in three cavity-nesting passerines. We studied western bluebirds (Sialia mexicana Swainson, 1832), mountain bluebirds (S. currucoides Bechstein, 1798), and tree swallows (Tachycineta bicolor Vieillot, 1808) breeding in artificial nest boxes at sites across 70 km of the Okanagan Valley of British Columbia, Canada. Sites varied in their degree of urbanization, from relatively undisturbed ranchland, to cultivated vineyards, to frequently disturbed ‘suburban’ habitat, and boxes varied in type of entrance (slot or hole). Western bluebirds nested earlier in vineyards, and tree swallows produced significantly fewer fledglings in suburban habitat. In addition, tree swallows nested earlier and produced more fledglings in slot boxes. Our results suggest that conservation actions for cavity-nesting passerines may depend on the target species, which in turn should dictate the appropriate box type and habitat when erecting or replacing nest boxes.


Behaviour ◽  
1994 ◽  
Vol 131 (1-2) ◽  
pp. 115-138 ◽  
Author(s):  
Tore Slagsvold ◽  
Glenn-Peter SÆTRE ◽  
Svein Dale

AbstractIn a number of passerine bird species, mated males sing at dawn and this song activity peaks in the fertile period of the mate. We present the hypothesis that an important function of such dawn singing is to maintain the territory. We suggest that mate guarding and territorial defence are demanding and often mutually exclusive activities. Losing paternity is so costly that males give priority to mate guarding. Males therefore use the early morning period, before their mate emerges from the roost, to claim territory ownership. We report some preliminary tests of this hypothesis from a study of great tits (Parus major). Simulating male intrusion by a playback experiment showed that the resident male was more often absent from central parts of the territory, following the mate, during the periods of nest building and egg laying than during incubation. This supports the assumption of conflicting demands between mate following and territorial defence. From the hypothesis we expected males to spend effort in defending their territory as soon as they were free to do so. Consistent with this prediction, we found that male song activity was high before the mate left the nest at dawn, when she temporarily visited the nest during the day, and when she entered the nest to roost at night. A female removal experiment showed that unmated males, having no mate to guard, sang as much at dawn as mated males. Only one of the eight widowed males succeeded to replace their mate. We discuss some alternative functions of dawn singing in the great tit, such as attraction of own mate, a replacement mate, and extra-pair mates. We conclude that the hypotheses are not mutually exclusive, and song may serve multiple purposes.


2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Mingju E ◽  
Tuo Wang ◽  
Shangyu Wang ◽  
Ye Gong ◽  
Jiangping Yu ◽  
...  

Abstract Background For secondary cavity-nesting bird species that do not add lining materials to nests, the presence of old nest material or organic remains that have accumulated within nest cavities from previous breeding events may be a cue of nest-site quality. These materials potentially contain information about past breeding success in con- and heterospecifics and may improve the thermal insulation of eggs during incubation. However, few studies have addressed whether the presence of old nest materials serves as a cue for cavity-nesting raptors when choosing specific nest sites. Methods We conducted a 9-year nest box experiment to test whether old nest materials from con- and heterospecifics serve as informative cues to the European Kestrel (Falco tinnunculus) when making nest selection decisions, as this species uses nest boxes without adding nesting material. Results The presence of old nest materials and entrance size best discriminated nest boxes occupied by European Kestrels from unoccupied boxes. Nest boxes containing conspecific organic remains, artificial dry leaf and branch material, and material left behind by Great Tits (Parus major) were reused at higher rates, especially those containing conspecific nest material, than nest boxes containing true or simulated nest materials from predators. In 2010, no single nest box was occupied by the same banded individual that occupied the box in the previous year (10 females and 2 males were banded in 2009). Conclusions European Kestrels preferred nest boxes containing old nest material over empty boxes, which is consistent with previous findings that they exploit con- and heterospecific cues when deciding where to settle and breed, as old nest or organic material provides substrate for incubating females. Kestrels may be able to assess the predation risks associated with a specific nest site based on experience or the presence of prey remains. The repeated use of nest boxes across breeding seasons by kestrels cannot be entirely ascribed to philopatry. This study provides evidence that old nest materials are potentially used as informative cues when making nest-site selection decisions in European Kestrels.


Author(s):  
Tore Slagsvold ◽  
Karen L. Wiebe

AbstractAmong species that use similar resources, an individual may benefit by observing and copying the behavioural decision of a heterospecific. We tested the hypothesis of heterospecific social learning in passerine birds, namely that a migrant species, the Pied Flycatcher Ficedula hypoleuca, uses external markings on the nest cavities of a resident species, the Great Tit Parus major, as cues when choosing a nest site. Others have suggested that prospecting flycatchers assess the clutch size of tit “demonstrators” by entering their nest boxes and, assuming that a large clutch indicates a high-quality individual, will copy the nest appearance of tits with large, but not small clutches. During a 4-year period in Norway, we designed a similar study but did not find that flycatchers based their nest choice on the clutch size of tits. Neither were there any relationships between clutch size of the tit and its laying date, incubation behaviour, or the number of eggs visible through nest material during egg-laying so Pied Flycatchers did not use these indirect cues to assess quality of the tutor. Filming of tit nests showed that prospecting flycatchers did not enter tit nest boxes to assess the content. Indeed, incubating female tits only left their nest boxes for short bouts of unpredictable duration so there was little opportunity for flycatchers to inspect the nest contents unnoticed. Our study calls into question the mechanism of using the content of tit nests as public information for choosing traits of nest sites based on external characteristics. We suggest that similar studies of nest site choice in relation to possible social information transfer be replicated more widely.


Sign in / Sign up

Export Citation Format

Share Document