Nest Cavities Research Articles

Anatomy and Immunohistochemistry of Woodpecker Tail Muscles.

Woodpeckers (Order Piciformes) belong to a group of birds characterized by their hammering capabilities in which the bill is utilized as a tool to probe for food and to excavate nest cavities. They have numerous specializations for this behavior, including their bill and tongue, feet for gripping vertical tree trunks, and tail feathers with thickened shafts to provide stability as a postural appendage. We hypothesized that (1) woodpecker tail musculature is also modified for clinging behaviors with a heterogeneous distribution of fast and slow muscle fibers, and that (2) the tree-trunk foraging Hairy Woodpeckers would have more slow muscle fibers in their M. depressor caudae than Northern Flickers, which forage on the ground where they probe the substrate for insects. We performed immunohistochemistry to identify the fiber type distributions for tail muscles Mm. caudofemoralis pars caudalis, lateralis caudae, levator caudae, and depressor caudae in four Hairy Woodpeckers and five Northern Flickers. Our results show that these tail muscles in the two woodpecker species are comprised of a majority of fast muscle fibers common among dynamic locomotor muscles. Interestingly, we report a functionally-significant distribution of slow muscle fibers in M. depressor caudae predicted to be utilized in propping of the tail during tree climbing and support. Further, we found more slow fibers (13.80% ± 4.49%) in the trunk-foraging Hairy Woodpeckers compared with the ground-foraging Northern Flicker (7.40% ± 4.95%), which we interpret to be related to the trunk-foraging habits of Hairy Woodpeckers.

Orientation, thermal characteristics and structural dimensions of Mangrove Kingfisher Halcyon senegaloides nest cavities in arboreal termitaria in central Mozambique

The breeding ecology of the Mangrove Kingfisher Halcyon senegaloides (family Alcedinidae) remains poorly known. While the few nests recorded in southern and East Africa have been in tree hollows, a seasonal population in central Mozambique woodland breeds in cavities in arboreal termitaria. Despite this breeding strategy being widely recorded in many tropical kingfisher species, it has received little research attention in the Afrotropical realm. We report on the siting and structural characteristics of arboreal termitaria used as nesting sites by Mangrove Kingfishers in central Mozambique and document the thermal dynamics of a nesting cavity in an arboreal termitarium. Arboreal termitaria (average volume 40.1 ± 23.8 l) occurred at a density of 0.52 ± 0.22 termitaria ha−1 in large trees or shrubs, mostly of the families Fabaceae and Malvaceae. Termitaria containing nest cavities were situated 10.8 ± 3.1 m above the ground, and most nests (78.6%) faced north. Nest cavity temperatures averaged 31.4 ± 2.6 °C, which is warmer and more stable than the average ambient temperatures of 28.7 ± 4.0 °C. ‘Carton’ termitaria (comprising a mixture of faecal matter and wood fragments) are thus believed to confer a thermal advantage for summer-nesting Mangrove Kingfishers.

A descriptive study of the biometrics of the stingless bee Lepidotrigona flavibasis in northern Thailand

Stingless bees play a crucial role in tropical and subtropical ecosystems, contributing significantly to biodiversity and pollination services. The species Lepidotrigona flavibasis (Cockerell 1929) (Apidae: Meliponini), found in Southeast Asia, has attracted attention for its unique nesting habits and valuable honey production. The objective of this study was to compare colony size and productivity between different nesting cavities. Twelve colonies of L. flavibasis were collected in Chiang Mai province, Thailand, to study biometrical data. Six colonies were housed in hollowed logs, previously occupied by Apis cerana, and six in bamboo cavities. The colony ages ranged from 8 months to 5 years. This study found that log cavity colonies had larger populations and more brood cells than bamboo cavity colonies. Results show that log cavity colonies had an average number of workers (3,842.6 ± 2036), drones (288.2 ± 511), brood cells (5,914.5 ± 3026), honey pots (290.5 ± 210), and pollen pots (96.8 ± 90). The bamboo cavity colonies were found to have an average number of workers (1,628.2 ± 575), drones (64 ± 58), brood cells (2,333.7 ± 1875), honey pots (127.3 ± 95), and pollen pots (94.8 ± 57). Overall, the log cavity colonies demonstrated greater colony size and productivity regarding adult bees and brood.

Diapause, pollen ball incidence, and overwintering energetics in the alfalfa leafcutting bee, Megachile rotundata

IntroductionWarming summer temperatures have the potential to harm managed pollinators, impacting both summer performance and overwintering success. The alfalfa leafcutting bee, Megachile rotundata, is a solitary bee used for commercial pollination of alfalfa. M. rotundata undergoes facultative diapause in the prepupal stage. Prepupae that diapause early in the season are exposed to warm temperatures for a longer period of time than the individuals that start diapause closer to fall, which may reduce lipid reserves required for overwintering survival. Warm temperatures may also contribute to pollen ball incidence, which is when a provision is present but there is no sign of a larva in the brood cell. Our goal was to identify factors that regulate diapause and pollen ball incidence and examine effects of pre-wintering field conditions on post-overwintering energy reserves in M. rotundata.MethodsNest boxes were installed near Fargo, ND, Laramie, WY, and Las Cruces, NM, which exposed bees to different photoperiods and thermal regimes. Three nest boxes were placed at each site. We monitored nesting conditions and diapause and pollen ball incidence throughout the season. Lipids, sugars, and glycogen reserves were measured in adults after overwintering.Results and DiscussionOur models indicate that most of the variation in diapause incidence was explained by nest, with individuals within a nest tending to have the same diapause outcome. This suggests that the environmental conditions experienced by the mother, or genetic predisposition, influences offspring diapause. We also found evidence that high cavity temperatures can cause diapause aversion. In addition, our study is the first to link high nesting cavity temperatures to increased pollen ball incidence. Exposure to stressful temperatures during development and early diapause resulted in an increase in adult lipid reserves after overwintering. Adult sugar and glycogen reserves were not affected by exposure to warm temperatures during development and early diapause. In conclusion, maternal effects and temperature were important factors for diapause and pollen ball incidence in M. rotundata with macronutrient reserves similar for early and late season bees.

Ecosystem engineers show variable impacts on habitat availability for cavity nesters in South American temperate forests

Ecosystem engineers show variable impacts on habitat availability for cavity nesters in South American temperate forests

Intrusion of birds into nest cavities depends on the presence of feathers in the cavity and not on species of nest owner

AbstractMost animals live and move in a landscape in which the risk of predation varies spatially and temporally, that is, a “landscape of fear” which may strongly affect their ecology and behaviour. Cavity‐nesting birds prospecting for nest sites are often forced to investigate unfamiliar, dark holes that may be dangerous to enter because they may conceal an aggressive nesting bird or a predator. The Fear of Feathers Hypothesis posits that some birds such as blue tits Cyanistes caeruleus, add large, conspicuous feathers on top of their own nest to exploit the fear of potential nest usurpers or brood parasites. Feathers may trigger fear in prospecting birds either because the feathers obstruct the view of the cavity interior, and/or because the feathers may be perceived as recent prey remains and suggest the predator will return. Here I studied the prospecting behaviour of unmated male pied flycatchers Ficedula hypoleuca by letting them choose between a dyad of nest boxes where one contained a nest of a great tit Parus major and one a nest of a blue tit. The objective was to test whether the presence of feathers would have a stronger repelling effect than the species that had built the nest. Great tits are larger than blue tits and may represent a greater threat to intruding flycatchers. However, blue tits but not great tits, often decorate their nest with large, conspicuous feathers. Consistent with the Fear of Feathers Hypothesis, flycatchers hesitated longer to enter blue tit than great tit nests but only if the blue tit nest contained feathers. The study has relevance to many species of birds that decorate their nest with feathers. It shows that a landscape may include aspects of fear that are important to animal behaviour although they may seem subtle and are easily overlooked.

Tree cavity density is a limiting factor for a secondary cavity nester in second-growth Andean temperate rainforests

Abstract Cavity-nesting bird populations are most frequently limited by the number of tree cavities available in second-growth forests. However, this possible limitation of a key resource is less clear in old-growth forests. We compared forest attributes (i.e., basal area, density of larger trees, density of dead trees, and tree cavity density) in second-growth and old-growth stands in Andean temperate rainforests in southern Chile. To examine the role of nest-site availability in limiting the populations of Aphrastura spinicauda (Thorn-Tailed Rayadito), a secondary cavity-nesting bird species, we conducted an experiment in which nest boxes were added and removed in old-growth and second-growth forests during a 5-yr period (2008–2013). In old-growth forests, as compared to second-growth forests, we found a more than double basal area (99.6 vs. 43.7 m2 ha–1), a three times higher density of larger trees (88.2 vs. 36.4 trees ha–1), and a 1.5 times higher number of small cavities (25.9 vs. 10.3 cavities ha–1). The density of cavities also strongly increased with tree diameter and basal area. In second-growth forests, A. spinicauda showed a strong response to the addition and removal of nest boxes, with population abundance increasing by 13% and then decreasing by 50%, respectively. In contrast, we found no impact in old-growth stands. Our experiment emphasizes the importance of maintaining large and dead trees in second-growth, disturbed, and managed forests. These trees provide suitable cavities for A. spinicauda, and likely many other secondary cavity nesters, increasing their abundances in a Globally significant Biodiversity Hotspot in southern South America.

Distribution of brood of the acorn ant Temnothorax crassispinus in artificial nests after forced migration

Nest sites are important for social insects, as they provide refuge against enemies and ensure optimal conditions for the brood development. In large nests, the different chambers can be used for different reasons; for example, for food storage or as a brood chamber. Acorn ants from the genus Temnothorax dwell in small cavities in acorns and wood; however, even such small chambers can have a high degree of spatial heterogeneity. During this study, the distribution of brood items of the acorn ant Temnothorax crassispinus inside artificial nest cavities composed of three chambers in a linear system was analysed. 29 ant colonies were photographed 13 times during a period of approximately one month: during three consecutive days, and after forced migrations. I found that the distribution of the brood inside the nest cavity was similar during the consecutive days; however, after the forced migration, the distribution typically changed. Almost all the brood items were kept farther from the entrance. Keeping the brood farther from the entrance could be explained as a safer option.

Does Nesting Material Affect Wood Duck (Aix sponsa) Nest Box Selection, Reproduction, and Eggshell Bacteria?

Wood Ducks (Aix sponsa) are secondary cavity nesters that use natural cavities and artificial nest boxes, the latter of which has been attributed to the recovery of populations across the southeastern US. Continual use of these boxes results in a buildup of bacteria, parasites, and other pathogens. To avoid the accumulation of these deleterious organisms, best management practices include the occasional removal of old nesting material (i.e., wood shavings) and replacement with fresh wood shavings. No studies have been performed on the effects of shaving material on nest box selection, nest success, and bacterial growth. We monitored 142 and 111 nest boxes in Florida and Georgia, USA, respectively, and filled a random sample with aspen or cedar shavings. We then swabbed the surface of 144 and 150 eggs during 2020 and 2021, respectively, to screen for culturable bacteria. We detected no effect of shaving type on nest box selection, nest success, or egg surface bacterial growth. We found 3-8 bacterial colony types (1-123 colony-forming units [CFU]/box) and 1-8 bacterial colony types (3-382 CFU/box) among the Georgia and Florida samples, respectively. We detected no effect from shaving type on Wood Duck reproduction or bacterial growth in the sampled nest boxes. We concluded that both shaving types are suitable nesting materials for box-nesting Wood Duck populations and the continued use of either would be a reasonable decision for managers.

Diet and multi-taxa neo-taphonomy of Glaucidium nana (Aves, Strigiformes) from southeastern Patagonia and comparisons with G. brasilianum from Chaco forest and other owls

ABSTRACT The diet and neo-taphonomy of Glaucidium nana (Aves, Strigiformes), evaluated from pellets and leftover prey recovered in nest-boxes from a National Park of southeastern Patagonia are studied. Comparative evaluations are conducted with microvertebrate samples obtained from other raptors, particularly those of G. brasilianum from the Chaco forest in Argentina. The diet of G. nana reported here agrees with the generalist trophic behaviour of this species already documented, which feeds on invertebrate (insects and arachnids) and vertebrate prey (amphibian, reptiles, birds and mammals), mainly caviomorph rodents heavier than itself. The taphonomic attributes allow us to place the two species of Glaucidium in the moderate modification category. They could deposit their diet remains in several open-air sites, mainly in wooded and rocky areas, where the cavity nests are located. Later, their bone accumulation –composed of microvertebrates with evidence of moderate bone modifications and/or with articulated skulls and limb bones without digestive corrosion- might integrate into the lithosphere. Understanding the trophic interactions between predators and prey, and their taphonomic signatures, as well as identifying their nesting areas, is crucial for archaeology/palaeontology analysis and for developing effective conservation and management strategies within protected areas.

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.

Nest site selection of cavity-nesting birds at Jahangirnagar University campus, Bangladesh

Understanding nest site selection by cavity-nesting birds is important for their conservation implications. We examined the preferences and characteristics of nesting trees and cavities used by cavity-nesting birds at Jahangirnagar University (JU) campus from January 2020 to October 2021. A total of 30 tree- cavity nests of 11 species of birds belonging to 4 orders and 7 families were recorded where 36% were primary excavators and 64% were secondary cavity-nesters. Out of 14 species of trees used in cavity-nesting, the most of the nests were built in Mahogany Swietenia mahagoni (n=8) followed by White siris Albizia procera (n=6) and Rain tree Samania saman (n=3). Diameter at breast height (DBH) of the nesting trees varied from 27 cm to 112 cm (52±23.2 cm). The highest mean DBH was recorded in Samania saman (85 cm) followed by Swietenia mahagoni (67 cm). Common Myna showed the widest selection of nesting tree species (n=9) followed by Black-rumped Flameback (n=4) and Lineated Barbet (n=4). Majority of the nesting trees (87%) were found in roadside (within 1-5 m) vegetation while 60% nesting trees located within 30 m from the nearby water bodies. The cavity-nesting species preferred to nest between 2 m to 12 m (5.2±2.6 m) height from the ground level. The entrance width and the depth of tree holes (n=30) used by cavity-nesters varied from 5 cm to 22 cm (7.5±3.5 cm) and 13 cm to 45 cm (23.2±6.5 cm), respectively. Suitable cavities are critical for reproductive success of cavity-nesting birds and our results highlight the conservation value of cavity-bearing large trees to maintain a healthy population of cavity-nesting birds at JU campus. Jahangirnagar University J. Biol. Sci. 12(1 & 2): 1-10, 2023 (June & December)

Tree cavities and cavity users in two caldén forests of Argentina managed as a protected area or for cattle ranching

Animal populations that require tree cavities can be either limited or structured depending on the quality and availability of tree cavities in their ecosystems. Over the last century, the Caldén forest of Argentina has experienced severe habitat degradation due to anthropogenic activities. Here, we report the density and characteristics of cavities and their vertebrate users in areas of the Caldén forest with two different types of management: a protected area and an area with cattle ranching. The average density of cavities was 16.1 cavities/ha. However, the reserve's cavity density was four times higher than the ranch's (19.5 vs. 5.8 cavities/ha). The characteristics of the cavities and their support trees showed significant variations, but they were generally similar between sites. Forty-four vertebrate species use or may use tree cavities. The proportion of recorded species using cavities in the reserve was higher (30/41 vs. 6/32; p < 0.01). While most cavity users in the semi-arid forest are not threatened, this ecosystem has been dramatically fragmented, with only 11% of its original area remaining. If anthropogenic activities continue to alter this fragile ecosystem, it is possible that in the future, many species, including tree cavity nesters, will suffer a decline in their populations.

Attractant spray enhances nesting preference and reduces macroparasite infestation of Osmia cornuta

AbstractMason bees (Osmia. spp) can provide an alternative for crop pollination management in addition to the Western honeybees (Apis mellifera). Targeted evidence‐based guidelines can improve cost‐effective management of mason bees. Here, I test the effect of an attractant spray developed in the United States for improving the nesting preference for artificial trap nests of mason bees in Belgium. More specifically, this study investigates the effect of the attractant spray on the nesting preference and nesting performance of the European orchard bee (Osmia cornuta), as well as its effect on the infestation of nest‐associated macroparasites. The number of sealed nesting cavities was twice as high in the trap nests that were treated with the attractant spray. Nesting performance expressed as number of brood cells per cavity, successful cocoon formation, adult emergence, proportion of female bees in the offspring and the number of dead larvae was not different between the treated and the untreated nests. Overall infestation of macroparasites, and infestation of drosophilid flies in particular, were both twice as high in untreated nests. This study provides evidence that the attractant spray improves nesting preference and reduces macroparasite infestation in O. cornuta. The use of this attractant can provide growers and stakeholders with an effective management strategy to prevent infestation by macroparasites and promote efficient bee breeding.

Woodpecker Nest Cavity Orientation in Dry Conifer Forests of the Pacific Northwest, USA

Woodpecker Nest Cavity Orientation in Dry Conifer Forests of the Pacific Northwest, USA

First Report of Nesting Habits, Nest Architecture and Foraging Behaviour of the Stingless bee, Tetragonula (Tetragonula) ruficornis (Smith) (Hymenoptera: Apidae: Meliponini) from India

The present study aimed to understand nesting habits, nest architecture, and foraging behavior of the stingless bee, Tetragonula (Tetragonula) ruficornis Smith, a widespread species in the north Indian plains from Varanasi to Punjab. Among the 47 wild, unmanaged colonies studied, 27 were situated in the cavities of tree trunks and 20 in the cavities of building walls. The internal nest structure revealed that brood cells were arranged in clusters at the center of the cavity with encircling pollen and honey pots. Further, the natural nesting cavity’s total length, width, and height varied from 105 to 168 mm, 129 to 216 mm, and 283 to 472 mm, respectively. The foraging activity of outgoing and incoming foragers of T. ruficornis varied significantly during different hours of the day, across the seasons and prevailing weather conditions. Further, activity was limited to daytime from 08:00 to 18:00 h, with peak activity of outgoing and incoming forager bees between 10:00 and 12:00 h during all seasons. Irrespective of seasons, the foraging activity of outgoing, pollen, and nectar foragers was at its maximum at 12:00 h. However, foraging ceased during December and January due to low temperatures, while peak activity was observed during April. The foraging pattern showed a significant positive correlation with mean monthly maximum and minimum temperatures and a significant negative correlation with relative humidity. The current investigation delivers crucial information on nest architecture and foraging behavior, which could be exploited for designing bee hives and utilization in directed pollination services.

Volatiles of symbiotic bacterial origin explain ectoparasitism and fledging success of hoopoes

BackgroundSome parasites use olfactory cues to detect their hosts and, since bacterial symbionts are partially responsible for animal odours, they could influence host parasitism. By autoclaving nest materials of hoopoe (Upupa epops) nests before reproduction started, we explored the hypothetical links between host-associated bacteria, volatiles and parasitism. During the nestling stage, we (i) estimated the level of ectoparasitism by chewing lice (Suborder Mallophaga) in adult hoopoe females and by Carnus haemapterus flies in nestlings, and (ii) characterized microbial communities and volatile profiles of nest environments (nest material and nest cavity, respectively) and uropygial secretions.ResultsExperimental nests had less diverse bacterial communities and more diverse volatile profiles than control nests, while occupants experienced lower intensity of parasitism in experimental than in control nests. The experiment also affected beta diversity of the microbial communities of nest material and of the volatiles of the nestling uropygial secretions. Moreover, microbial communities of uropygial secretions and of nest materials covaried with their volatile profiles, while the volatile profile of the bird secretions explained nest volatile profile. Finally, a subset of the volatiles and bacteria detected in the nest material and uropygial secretions were associated with the ectoparasitism intensity of both adult females and nestlings, and with fledging success.ConclusionsThese results show that a component of animal odours is linked with the microbial communities of the host and its reproductive environment, and emphasize that the associations between bacteria, ectoparasitism and reproductive success are partially mediated by volatiles of bacterial origin. Future work should focus on mechanisms underlying the detected patterns.

Morphological and Histological Structure of Adexinal Glands of some Solitary Bee Species (Hymenoptera – Apoidea)

Solitary bees are diverse and very important for plant and crop pollination. They are extensively studied taxonomically, but little is known about their anatomy and physiology compared to honey bees. Dufour’s gland is important for many physiological functions in social and solitary bees. The present study addresses the morphological and histological structure of Dufour’s gland in ten bee species representing bee families Andrenidae, Colletidae, Halictidae, Melittidae, Megachilidae, and Apidae. Results indicated that the shape and size of the glands tend to differ from one species to the other. However, on histological bases, the intern seems to be the same among the secretion cell types. The gland varied in length and size in the studied species, probably due to nesting behavior differences: ground and cavity nesting. Further studies are needed to clarify the different secretions produced by Dufour’s gland and their functions in each species.

Eviction-driven infanticide and sexually selected adoption and infanticide in a neotropical parrot

Infanticide and adoption have been attributed to sexual selection, where an individual later reproduces with the parent whose offspring it killed or adopted. While sexually selected infanticide is well known, evidence for sexually selected adoption is anecdotal. We report on both behaviors at 346 nests over 27 y in green-rumped parrotlets (Forpus passerinus) in Venezuela. Parrotlets are monogamous with long-term pair bonds, exhibit a strongly male-biased adult sex ratio, and nest in cavities that are in short supply, creating intense competition for nest sites and mates. Infanticide attacks occurred at 256 nests in two distinct contexts: 1) Attacks were primarily committed by nonbreeding pairs (69%) attempting to evict parents from the cavity. Infanticide attacks per nest were positively correlated with population size and evicting pairs never adopted abandoned offspring. Competition for limited nest sites was a primary cause of eviction-driven infanticide, and 2) attacks occurred less frequently at nests where one mate died (31%), was perpetrated primarily by stepparents of both sexes, and was independent of population size. Thus, within a single species and mating system, infanticide occurred in multiple contexts due to multiple drivers. Nevertheless, 48% of stepparents of both sexes adopted offspring, and another 23% of stepfathers exhibited both infanticide and long-term care. Stepfathers were often young males who subsequently nested with widows, reaching earlier ages of first breeding than competitors and demonstrating sexually selected adoption. Adoption and infanticide conferred similar fitness benefits to stepfathers and appeared to be equivalent strategies driven by limited breeding opportunities, male-biased sex ratios, and long-term monogamy.

Which habitat factors affect the occurrence and richness of cavity nesters in parks along an urbanisation gradient? Recommendations for the management of greenery in an urban landscape

Which habitat factors affect the occurrence and richness of cavity nesters in parks along an urbanisation gradient? Recommendations for the management of greenery in an urban landscape