Nest Cup Research Articles

Predation of Rock Partridge Alectoris graeca saxatilis nests incubated by males and females in the French Alps

ABSTRACT Capsule The predation of incubated nests was investigated in an Alpine population of Rock Partridges, showing a double-nesting behaviour by females that can lay two clutches in succession, one incubated by the mated male and the second by the female. Aims To compare the nest predation rate and hatching success between incubating males and females in relation to the potential effects of year, nest age, and environmental characteristics (presence of nest cameras, visibility of the clutch, and vegetation cover around the nest). Methods The fate of 100 nests incubated by radio-tracked birds was monitored daily over 1738 days using cameras, and with temperature loggers placed in the nest cup. Nest predation rates and daily predation rates were calculated and modelled. Results Egg predation was the main cause of nest loss (87%) followed by predation of the incubating parent during recess periods off the nest (10%). Only mammals were identified as nest predators, and predation events were less frequent during the day than at night. We found no difference in predation rates between nests incubated by males or females. Daily and 25-day predation rates were calculated as 0.02 (95% CI: 0.01–0.03) and 0.39 (95% CI: 0.29–0.49), respectively. Median hatching success was 0.91 (n = 53 nests) and did not differ between sexes. Conclusions The similar level of nest predation between incubating males and females suggested a duplication of the reproductive output of a pair by double-nesting. Consequences of this breeding system were an increase in productivity at the population level. There was no difference in hatching success in nests incubated by either sex and there were no observations of surviving males deserting their nests, suggesting that care during incubation was similar in males and females. Variation in the rate of double-nesting may contribute more than nest predation to the annual variation in reproductive output.

Nest site correlates with nest type and body size in Troglodytidae passerines.

Nest characteristics are highly variable in the Passeriformes, but the macroevolutionary patterns observable for birds in general are not necessarily valid for specific families, suggesting that both global and within-family studies are needed. Here, we used phylogenetic comparative methods to address the evolutionary patterns of nest type, nest site and habitat in the Troglodytidae, a passerine group with diversified nest and habitat characteristics. The common ancestor of the Troglodytidae likely constructed enclosed nests within sheltered sites (cavity or crevice), but the radiation of the group was characterized by (i) shifts to exposed nest sites (vegetation) with retention of enclosed nests or (ii) retention of sheltered sites with nest simplification (cup nests). Nest site and nest type presented strong phylogenetic conservatism and evolved interdependently, while habitat was poorly correlated with nest evolution. A phylogenetic mixed modelling approach showed that sheltered nest sites were associated with small body size, likely to avoid competition with other animals for these places. With these results, we improve the understanding of nest character evolution in the Troglodytidae and reveal evolutionary aspects not observed so far for passerine birds.

Conflicting cognitive decisions: Does egg retrieval modify egg rejection in a host of an obligate brood parasite?

AbstractEgg retrieval is an ancient behaviour displayed by birds in which a displaced egg is transferred back into the nest. Egg rejection, in contrast, is a recently evolved adaptation by hosts of brood parasites in which an egg is removed from a nest. These conflicting behaviours are both adaptive because they prevent reproductive losses, but egg retrieval may benefit brood parasites if hosts retrieve parasitic eggs into their nests. We examined these conflicting cognitive processes in the prothonotary warbler (Protonotaria citrea), a cavity‐nesting host of the brown‐headed cowbird (Molothrus ater). Eggs and nestlings are occasionally found on the rims of warbler nest cavities. We determined how this happened using video cameras and tested whether warblers retrieved their own eggs more often than cowbird eggs. We also determined if shape affects retrieval and rejection by placing cylinders inside nest cups or onto nest rims. We found that eggs were displaced by rapidly departing warblers whose nests are constantly prospected by nest competitors and brood parasites. Warblers retrieved their eggs (29%) and cowbird eggs (19%) at similar rates, and never rejected cowbird eggs after retrieval. Warblers removed most cylinders from nest rims and cups (89% and 78%, respectively), and never retrieved them. Warblers have retained egg retrieval at a low level and its expression is costly because they only retrieve a low level of their own eggs and also retrieve cowbird eggs, which benefits the brood parasite.

Architecture differentially affects thermal properties of Song Thrush Turdus philomelos nest walls

ABSTRACT Thermistors embedded on and within the nest wall were used to measure the changes in temperature between different parts of the architecture of the wall of Song Thrush nests as heat from a light bulb was conducted across the wall. The wood pulp forming the nest cup provided the greatest resistance to heat loss across the nest wall. Despite differences in nest mass and architecture, thermal conductance for Song Thrush nest walls were not statistically different from values previously reported for Common Blackbird Turdus merula nests. Song Thrush nests constructed over many years in the same geographical location exhibited an increase in the thickness of the wood pulp cup and a reduction in thermal conductance, i.e. the most recent nests were better insulated. However, nest mass or thermal insulation did not affect reproductive success between years.

Does the Provisioning of Artificial Nest Cups and Nesting Structures Help House Martins Delichon urbicum?

Does the Provisioning of Artificial Nest Cups and Nesting Structures Help House Martins Delichon urbicum?

Assessing timing of fledging in a cavity-nesting passerine using temperature data loggers

In altricial birds, the length of the nestling period, i.e. time from hatching until fledging (young leaving the nest) varies within and between species. In general, however, variation in the time of fledging and factors mediating such variation remain largely unexplored. To assess the time of nestlings leaving the nest, daily observer visits to the nest are usually done in the predicted fledging period. However, this might initiate premature fledging of young and/or increase the predation risk. The application of iButtons – coin-sized temperature data loggers, which are increasingly used in ornithological studies – may help to overcome these obstacles. We tested whether nest temperatures recorded with iButtons might be used to identify the date and hour of young fledging, i.e. when the last nestling in the brood left the nest, in a small cavity-nesting passerine – the Great Tit (Parus major). We installed iButtons in 38 nests when nestlings were 14–15 days old (hatching day = day 0) and verified the presence of nestlings during daily inspections starting on day 17 post-hatching or later. We found that the day of fledging could be accurately determined based on the difference between the temperature of the nest cup and the outside. The age of nestlings ranged between 17 and 22 days at fledging, with nearly 58% of broods fledging at the age of 20 and 21 days. The majority (81.6%) of broods fledged within 6 h after sunrise. We discuss the advantages and disadvantages of using iButtons to identify fledging time in altricial birds.

Agriculture and hot temperatures interactively erode the nest success of habitat generalist birds across the United States.

Habitat conversion and climate change are fundamental drivers of biodiversity loss worldwide but are often analyzed in isolation. We used a continental-scale, decades-long database of more than 150,000 bird nesting attempts to explore how extreme heat affects avian reproduction in forests, grasslands, and agricultural and developed areas across the US. We found that in forests, extreme heat increased nest success, but birds nesting in agricultural settings were much less likely to successfully fledge young when temperatures reached anomalously high levels. Species that build exposed cup nests and species of higher conservation concern were particularly vulnerable to maximum temperature anomalies in agricultural settings. Finally, future projections suggested that ongoing climate change may exacerbate the negative effects of habitat conversion on avian nesting success, thereby compromising conservation efforts in human-dominated landscapes.

Eggshell spots are an important cue for the egg retrieval behavior in two tit species.

It is a common occurrence for incubating female ground- or cavity-nesting birds to accidentally roll their own eggs out of the nest cup. To correctly roll eggs that are not in the nest cup back to the nest, birds must be able to discriminate between their eggs and things around their nests that could be easily confused for their eggs (e.g., egg-shaped stones or other birds' eggs). Moreover, there may be a strong interaction between egg retrieval and egg rejection behaviors in the context of avian brood parasitism where recognition and rejection of alien eggs is an effective means for hosts to defend against cuckoo parasitism. It has been shown that green-backed tits (Parus monticolus) and Japanese tits (P. minor) in China have strong egg recognition ability and are able to reject nonmimetic eggs in the nest. Eggshell spots play an essential role in the egg rejection behavior of these two tit hosts. This study investigated the egg retrieval behavior of green-backed tits and Japanese tits by adding one experimental egg to the nest corner to explore whether eggshell spots also play a role in the process of egg retrieval. The results revealed significant differences in the retrieval rates of white-rumped munia (Lonchura striata) eggs painted with spots, Japanese tits' own true eggs, and unpainted, pure white-white-rumped munia eggs. The retrieval rate of white-white-rumped munia eggs was significantly lower than that of spotted white-rumped munia eggs and Japanese tits' own spotted eggs. For green-backed tits, the retrieval rate of spotted white-rumped munia eggs in the nest corner was significantly higher than that of pure white-white-rumped munia eggs, while the rejection rate of spotted white-rumped munia eggs was significantly lower than that of pure white-white-rumped munia eggs. These findings indicate that eggshell spots play a key role in the egg retrieval of green-backed tits and Japanese tits.

Evolution of nest architecture in tyrant flycatchers and allies.

Innovations in nest design are thought to be one potential factor in the evolutionary success of passerine birds (order: Passeriformes), which colonized new ecological niches as they diversified in the Oligocene and Miocene. In particular, tyrant flycatchers and their allies (parvorder: Tyrannida) are an extremely diverse group of New World suboscine passerines occupying a wide range of habitats and exhibiting substantial extant variation in nest design. To explore the evolution of nest architecture in this clade, we first described nest traits across the Tyrannida phylogeny and estimated ancestral nest conditions. We then quantified macroevolutionary transition rates between nest types, examined a potential coevolutionary relationship between nest type and habitat, and used phylogenetic mixed models to determine possible ecological and environmental correlates of nest design. The Tyrannida ancestor probably built a cup nest in a closed habitat, and dome nests independently evolved at least 15 times within this group. Both cup- and dome-nesting species diversified into semi-open and open habitats, and we did not detect a coevolutionary relationship between nest type and habitat. Furthermore, nest type was not significantly correlated with several key ecological, life-history and environmental traits, suggesting that broad variation in Tyrannida nest architecture may not easily be explained by a single factor. This article is part of the theme issue 'The evolutionary ecology of nests: a cross-taxon approach'.

Variation in nest-building behaviour in birds: a multi-species approach.

Researchers have long suggested that animals with greater behavioural flexibility will be more likely to survive in face of environmental changes. However, it is unknown how this varies across species. Nest building is a behaviour directly related to the reproduction and survival of species by conferring protection from external environmental conditions. The study of nests offers a window into the behaviour of birds, and variation in nest morphology is necessarily linked to variation in building behaviours. We test whether variation in nest morphology is phylogenetically conserved by using data on nest morphology from 55 passerine species (>700 specimens) and measuring intraspecific variability in nest structure. We found that species mean and within-species variation in nest morphology are phylogenetically conserved, and that species with domed nests presented higher levels of nest morphology variation than cup nest species. We also revealed that the capacity of species to present innovative behaviours is not linked with how they vary nest morphology. Moreover, we revealed that nests from species with larger variation in clutch size and that are built by single parents are more variable. Our results help in the understanding of how behaviour and extended phenotypes evolve, and highlight the importance of exploring the phylogenetic history of behavioural flexibility when trying to predict the capacity of species to respond to novel challenges. This article is part of the theme issue 'The evolutionary ecology of nests: a cross-taxon approach'.

The evolution of nest site use and nest architecture in modern birds and their ancestors.

The evolution of nest site use and nest architecture in the non-avian ancestors of birds remains poorly understood because nest structures do not preserve well as fossils. Nevertheless, the evidence suggests that the earliest dinosaurs probably buried eggs below ground and covered them with soil so that heat from the substrate fuelled embryo development, while some later dinosaurs laid partially exposed clutches where adults incubated them and protected them from predators and parasites. The nests of euornithine birds-the precursors to modern birds-were probably partially open and the neornithine birds-or modern birds-were probably the first to build fully exposed nests. The shift towards smaller, open cup nests has been accompanied by shifts in reproductive traits, with female birds having one functioning ovary in contrast to the two ovaries of crocodilians and many non-avian dinosaurs. The evolutionary trend among extant birds and their ancestors has been toward the evolution of greater cognitive abilities to construct in a wider diversity of sites and providing more care for significantly fewer, increasingly altricial, offspring. The highly derived passerines reflect this pattern with many species building small, architecturally complex nests in open sites and investing significant care into altricial young. This article is part of the theme issue 'The evolutionary ecology of nests: a cross-taxon approach'.

Nesting behavior of the Chestnut-crowned Gnateater, Conopophaga castaneiceps (Aves: Conopophagidae)

ABSTRACT The chestnut-crowned gnateater (Conopophaga castaneiceps) inhabits the Andean mountains, from Colombia to Peru, between 500 and 2000 m. Our study provides new information on the nesting biology of C. castaneiceps; specifically, we describe hitherto unknown aspects such as eggs, nestling development, incubation and feeding behaviours. Three nests were monitored during two breeding seasons (2014–2015) in Tatamá National Park, Risaralda, Colombia. Cup nests contained a clutch of two creamy eggs with reddish dots scattered throughout the shell. On average, the parents incubated 58% of their time, with similar duration of the off- (77 ± 48.2 min) and on-bouts (73 ± 41.7 min). A few days before nestlings abandoned the nest (11–12-day-old nestlings), parents conducted 6.8 ± 1.6 feeding trips per hour (N = 25 hours) during the daytime. Based on one nest, the nestling period lasted 17 days, with a growth rate (K) of 0.4. The female had a higher investment during the nestling period, more brooding (t10 = 106.48, P < .001) and more feeding trips (t10 = 7.69, P < .001) compared to the male. Both parents conducted night brooding. Our study shows that nesting traits are conserved among Conopophaga species. Our novel information on nestling growth, incubation and feeding behaviour for C. castaneiceps advances our understanding of the gnateater’s poorly known nesting biology and will be key for future comparative studies.

Notes on the nesting and foraging behaviours of the Common Coot Fulica atra in the wetlands of Viluppuram District, Tamil Nadu, India

The nesting and foraging behaviours of the Common Coot Fulica atra were studied in the wetlands of Viluppuram District, Tamil Nadu during the breeding season. A total of 4,054 individuals of Common Coot including 467 juveniles and 1,327 nests were enumerated. Of the 1,327 nests, 1,191 were built on Ipomoea carnea vegetation and 136 on open water. The birds used twigs of Ipomoea carnea and various parts of eight other plant species as nest material. The nests were elliptical in shape, with flattened upper surfaces containing nest cup and a ramp-like structure each. 49.96 % of nests were found within 50 m distance from the edge of wetlands. A total of 16 plant species were identified as food sources including five algal species, such as Aphanothece stagnina, Spirogyra irregularis, Chara flaccida, C. vulgaris, and C. zeylanica. The Common Coots maintained strict territory during the breeding season and no other water birds were observed in the vicinity of their nesting and foraging sites. Even after completion of the breeding season, sporadic nesting was observed by a few pairs till June 2022.

Comparison of breeding strategies of two sympatric thrush species in an alpine environment

Closely related birds that occur sympatrically will inevitably differ in the acquisition of food resources, nest site selection, and breeding times. The successful coexistence of birds that breed in the same area can be determined by investigating how they divide limited resources and reduce interspecific competition. Our study area is located at the eastern foot of the Qinghai-Tibet Plateau, with a high altitude and low annual average temperature. In this study, the life history characteristics and reproductive ecological parameters of two closely related species, the Chestnut Thrush (Turdus rubrocanus) and the Kessler’s Thrush (Turdus kessleri), were compared in detail in April–July of 2020, 2021, and 2022 in the scrub along the Liqiu River in Xinduqiao Town, Tibetan Autonomous Prefecture of Garzê, Sichuan. The results showed no differences in nesting material, nest cup size, clutch size, feeding strategy of nestlings, brood food type, and reproductive effectiveness between the Chestnut Thrush and the Kessler’s Thrush. However, the Kessler’s Thrush had a higher nesting height, thicker nest wall, earlier breeding time, smaller eggs, fewer brooding frequent and a longer brooding time compared to the Chestnut Thrush. In addition, they invested more time in parental care, resulting in a faster growth and development rate. The results indicate that birds with different ranges and breeding in the same range show convergent and divergent life history characteristics in terms of reproductive biology. Chestnut Thrush with low reproductive altitude shows the characteristics of low-altitude bird reproduction in part of reproductive biology, while Kessler’s Thrush with high reproductive altitude shows the characteristics of high-altitude bird reproduction in part of reproductive biology.

Egg cooling associated with nest size in a passerine bird

Breeders evolved adaptive responses to rapid changes in ambient temperature. In birds, nests are expected to reduce egg cooling when the incubator is temporarily off the eggs. Here we present the results of two complementary laboratory experiments aiming at testing the association between egg cooling and the thickness of the nest under and surrounding the eggs in a non-domesticated avian model species (great tit, Parus major). To simulate incubation behaviour, we exposed nests with 4-egg clutches to a heat source until the eggs reached a normal incubation temperature (ca. 39 °C) and then recorded egg cooling 8 min after removal of the heat source, which corresponds to the time females generally leave eggs unattended during the incubation period. Eggs cooled more quickly when the nest layer under the eggs was thinner and when ambient temperature was cooler. We also show that the wall around the nest cup is important to buffer egg cooling. It is hypothesised that in bird nests, both the thickness of the material under the eggs, and the wall surrounding the nest cup interact to maintain a heat envelope around the eggs for the time the incubating parent is foraging. This could explain why the thickness of the nest base and wall are adjusted to the ambient temperature the birds experience during the nest building phase, to anticipate the thermal conditions during incubation and preserve egg viability.

Global drivers of variation in cup nest size in passerine birds.

The size of a bird's nest can play a key role in ensuring reproductive success and is determined by a variety of factors. The primary function of the nest is to protect offspring from the environment and predators. Field studies in a number of passerine species have indicated that higher-latitude populations in colder habitats build larger nests with thicker walls compared to lower-latitude populations, but that these larger nests are more vulnerable to predation. Increases in nest size can also be driven by sexual selection, as nest size can act as a signal of parental quality and prompt differential investment in other aspects of care. It is unknown, however, how these microevolutionary patterns translate to a macroevolutionary scale. Here, we investigate potential drivers of variation in the outer and inner volume of open cup nests using a large dataset of nest measurements from 1117 species of passerines breeding in a diverse range of environments. Our dataset is sourced primarily from the nest specimens at the Natural History Museum (UK), complemented with information from ornithological handbooks and online databases. We use phylogenetic comparative methods to test long-standing hypotheses about potential macroevolutionary correlates of nest size, namely nest location, clutch size and variables relating to parental care, together with environmental and geographical factors such as temperature, rainfall, latitude and insularity. After controlling for phylogeny and parental body size, we demonstrate that the outer volume of the nest is greater in colder climates, in island-dwelling species and in species that nest on cliffs or rocks. By contrast, the inner cup volume is associated solely with average clutch size, increasing with the number of chicks raised in the nest. We do not find evidence that nest size is related to the length of parental care for nestlings. Our study reveals that the average temperature in the breeding range, along with several key life-history traits and proxies of predation threat, shapes the global interspecific variation in passerine cup nest size. We also showcase the utility of museum nest collections-a historically underused resource-for large-scale studies of trait evolution.

Nesting jackdaws’ responses to human voices vary with local disturbance levels and the gender of the speaker

The ability to detect and respond to indicators of risk is vital for any animal and, for many species, humans represent a key threat. We investigated whether wild jackdaws, Corvus monedula , a species that thrives in anthropogenic environments but is regularly persecuted by people, associate human voices with differential degrees of risk and differ in their responses according to local levels of human disturbance. Playbacks showed that nesting females did not discriminate between the voices of familiar men who posed differing levels of threat, generalize to unfamiliar individuals with similar regional accents or discriminate between familiar and unfamiliar accents and voices. They were, however, considerably more wary towards male than female human voices, which may reflect the greater likelihood of negative experiences with men than women. Responses to playbacks also differed across fine-scale spatial locations: females nesting in areas of the colony with high levels of disturbance were less likely to leave the nest cup in response to playbacks and were more wary on their return to the nest than birds nesting in less disturbed areas. Nevertheless, levels of local disturbance did not influence reproductive success. Together these results indicate that, although vocal cues alone may not suffice for wild jackdaws to discriminate between individual humans or generalize across categories of people, sensitivity to cues of gender and local disturbance may help jackdaws to optimize their defensive behaviour and maintain breeding success. Further research into plastic responses towards indicators of human risk is vital to understand and mitigate the impacts of increasing urbanization on wildlife populations. • Nesting jackdaws were more fearful of playbacks of men's than women's voices. • No discrimination based on voices' accent, familiarity or threat level was found. • Birds used to high disturbance were less likely to inspect or flee voices. • Birds were warier when returning to nests in areas with high levels of disturbance.

NESTING PATTERN AND NEST PREDATORS OF SOME RESIDENT BIRDS OF ECOPARK, AN URBAN PARK IN KOLKATA, WEST BENGAL, INDIA

This Study was conducted from May 2020 to April 2022 at an urban park name Ecopark, located in Kolkata. A total of 116 nests of 38 birds were observed in this study area. Out of these 116 bird nests, 82 bird nests were found to have well developed young, while the other 34 were discovered to be unsuccess due to various reasons. Common Mynas (11) nests were found most. 8 types of nesting structures were observed during this survey namely Deep cup nest, Shallow cup nest, Hole nest, Platform nest, Dome shaped nest, Flat shaped nest, Hanging nest and pear-shaped nest. Hole nest (11) was the most visible nest in this study. Birds were seen nesting lowest on the surface of the water 0 ft to highest over 40 ft height. Storms, heavy rains, human activities, birds of prey, monitor lizards, snakes, rats, ants were indicated as the nests, chicks and birds egg damager.

Experimental warming during incubation improves cold tolerance of blue tit (Cyanistes caeruleus) chicks.

ABSTRACTClimate change and increasing air temperature may alter environmental conditions for developing birds, with a range of phenotypic consequences for offspring. The thermal environment during incubation may affect the trade-off between growth and thermoregulation, but the effects of temperature on the ontogeny of endothermy are not fully understood. Therefore, we experimentally tested whether heating the nest cup of Eurasian blue tits (Cyanistes caeruleus) during incubation would influence cold tolerance of the chicks after hatching. Chicks from both heated and control nests showed a decrease in cooling rate with age as they became increasingly endothermic and homeothermic. However, chicks from previously heated nests cooled at a lower rate per unit surface area and from across the whole body. These chicks also had a greater body mass during the first 12 days of life compared with chicks from control nests. Lower cooling rates in heated chicks may reflect greater thermogenic capacity or a reduced surface area to volume ratio owing to a greater body mass. Future projections for climate change predict rising air temperature and increased likelihood of heatwaves, even in temperate regions. Our results indicate that nest microclimate can affect thermoregulation in offspring, and thus may be used to predict some of the future physiological responses of birds to climate change during breeding.

NOTES ON THE NESTLING BIOLOGY OF THE GOLDEN-WINGED MANAKIN (MASIUS CHRYSOPTERUS)

A complete nesting information is available for 7.8% of the Manakin species; however, most of this information is fragmented and available mainly for lowland species. Hence, nesting information for highland species is scattered. Our study presents nesting information on a cloud forest Manakin species, the Golden-winged Manakin (Masius chrysopterus), which is distributed from western Colombia to northern Peru between 1000 and 2300m. We monitored 10 nests, from February through July in 2014 and 2015 at Parque Nacional Natural Tatamá, Colombia. We describe the nest, egg, and nestling, and provide information on incubation behavior and nestling feeding. The cup nest was similar to those found in most manakins. Eggs were creamy with brown spots concentrated at the base and measured 8.70± 0.89mm x 13.30 ± 0.39mm. The nestling growth rate (K) was 0.38. The incubation and nestling period were 22 and 16 days, respectively. The female conducted 70 off-bout trips day-1 that lasted on average 8.24 ± 5.44min, with 78% nest attentiveness. This study provides the most complete nesting data for a cloud forest manakin. Overall, M. chrysopterus incubation and nestling period are longer when compared to other manakin species. But the nest structure and composition, and eggs coloration concurred with other species.