Inter-nest Distance Research Articles

Geographic, ecological, and temporal patterns of seabird mortality during the 2022 HPAI H5N1 outbreak on the island of Newfoundland

Highly pathogenic avian influenza H5N1 caused mass mortality of wildlife across the North Atlantic in 2022. Following European outbreaks, the first North American case was detected on the island of Newfoundland, Canada in November 2021, before spreading throughout North America. During the following summer, Newfoundland and surrounding islands (NFLD) experienced one of the most significant mortalities in Canadian provinces, with seabirds being the most affected taxa. From surveys and citizen reports, we estimate that 13517 mortalities that can be attributed to HPAI occurred in NFLD from April to September 2022. Most estimated mortalities were among Northern Gannets (Morus bassanus, Linnaeus, 1758) (6596), Common Murres (Uria aalge, Pontoppidan, 1763) (5992), Atlantic Puffins (Fratercula arctica, Linnaeus, 1758) (282), and Black-legged Kittiwakes (Rissa tridactyla, Linnaeus, 1758) (217). Mortality reports moved from west to east along the southern then eastern NFLD coast and peaked in July and August. We formulated exploratory hypotheses regarding traits that could contribute to infection and mortality. Species differences in mortality most strongly associated with inter-nest distance, breeding phenology, and at-sea overlap with allospecifics from other colonies. Unprecedented seabird mortality and ongoing transmission within the circulating avian influenza viruses highlight the need for continued monitoring and development of conservation strategies.

Social associations are predicted by nest proximity but not kinship in a free-living social parrot

Abstract Social associations among conspecifics are typically non-random, often being a function of relatedness, familiarity, or spatial distributions. The aim of this study was to combine field observations with molecular genetic techniques and social network analysis to investigate the predictors of social associations in free-living monk parakeets, Myiopsitta monachus. Monk parakeets are non-territorial parrots whose nests are often aggregated, with relatives clustered in kin neighbourhoods and within cooperatively breeding groups. First, we characterized social associations when away from the nest, showing that individuals typically had a few strong social ties. Second, we investigated whether these social associations were related to nest proximity or genetic relatedness. The strength of association decreased with increasing inter-nest distance, but there was negligible influence of relatedness on the strength of associations. These patterns did not differ between same-sex and opposite-sex dyads. Finally, we investigated whether members of breeding pairs were close social associates, finding that in most cases the closest associate of an individual was their mate, although social bonds also existed outside of the pair; members of breeding groups also associated closely when foraging. Social associations are poorly known in parrots owing to methodological challenges, hence our results add to the limited knowledge of sociality in this taxon.

Demographic composition, post-release and natal dispersal, and breeding success of the reintroduced Oriental Stork Ciconia boyciana

Summary Species restoration through reintroduction and reinforcement is widely considered as an effective method for the conservation of threatened animals. Although these approaches have been increasingly implemented over the last half-century, many attempts have failed. Dispersal behaviour is one of the key factors determining reintroduction success. We reported the demographic composition and dispersal pattern (i.e., post-release and natal dispersal) of a reintroduced Oriental Stork Ciconia boyciana population in Japan and identified the determinants of breeding success in 2005–2019. We hypothesized that one of the key determinants of breeding success is the density-dependent effect through post-release and natal dispersal. The F1 generation occurrence corresponded to two years, F2 to seven, F3 to 11, and F4 to 14 years after initial reintroduction. Wild-born birds accounted for 74% of the reintroduced population at F4 occurrence. Post-release dispersal distances were shorter than natal dispersal. Inter-nest distance was selected as the key factor determining breeding success. These results may have been due to feeding habitat restoration and conspecific interactions. In conclusion, steady recruitment to the next generation is thought to be due to a moderate natal dispersal and the subsequent low breeding density of wild-born birds.

Predictors of Osprey Nest Success in a Highly Urbanized Environment

ABSTRACT Ospreys (Pandion haliaetus) are adaptable fish-eating raptors that readily nest on artificial structures in heavily human-dominated areas. Although the Osprey is a well-studied species, few researchers have investigated the factors that influence nest success and productivity in an urban environment. We monitored Osprey nests from 2013 to 2017 in highly urbanized Pinellas County, located on the west coast of central Florida, USA. We used logistic exposure models to assess the effects of timing of nesting, nest attributes (nest substrate, height), and landscape-level variables (inter-nest distance, distance to water, and surrounding habitat type) on daily survival rate (DSR) of Osprey nests. The number of active nests (i.e., nests with eggs) in the study area ranged from 53 in 2013 to 79 in 2016, with an overall total of 329 during the 5-yr study. Although most nests produced at least one young near fledging age, 131 of the nests failed. We attributed 45% of nest failures to storm events and 50% to unknown causes. The best logistic exposure model specification included only two variables: the discrete variable representing the date incubation started and the nominal variable indicating the year 2015. Osprey nests initiated earlier in the season were more likely to survive, and later nests (initiated after 22 April) averaged only one fledgling each. Osprey nests in 2015 had the highest DSR and relatively few failed due to storms. Our results supported previous research indicating that early nesters were more successful than late nesters. Our results also indicate that storms may play a role in nest success of Ospreys in Florida. Other variables, such as the amount of urbanized land surrounding Osprey nests did not appear to influence nest survival, indicating that Ospreys can be productive even in highly urban environments.

Effect of host species, host nest density and nest size on the occurrence of the shining guest ant Formicoxenus nitidulus (Hymenoptera: Formicidae)

Understanding habitat requirements of species is important in conservation. As an obligate ant nest associate, the survival of the globally vulnerable shining guest ant, Formicoxenus nitidulus, is strictly tied to that of its hosts (mound building Formica ants). We investigated how host species, nest density, inter-nest distance and nest mound size relate to the occurrence of F. nitidulus. In total, 166 red wood ant nests were surveyed in SW Finland (120 Formica polyctena, 25 F. rufa, 14 F. aquilonia, 5 F. pratensis, and 2 F. lugubris). Overall, F. nitidulus was found in 60% of the nests. For the actual analysis, only F. polyctena and F. rufa nests were included due to the small number of other nests. F. nitidulus was more likely to be found among F. polyctena than F. rufa. Also, while inter-nest distance was not important, a high nest density, commonly found in polydomous (multi-nest) wood ant colonies, was beneficial for F. nitidulus. The guest ant was also more likely to be found in large host nests than small nests. Thus, our results show that the best habitat for the guest ant is a dense population of host nest mounds with a high proportion of large mounds. Conservation efforts should be directed at keeping the quality of the red wood ant habitats high to preserve their current populations and to increase colonization. This will not only benefit the guest ant, but also a plethora of other species, and help in maintaining the biodiversity of forests.

Selection for protection from insolation results in the visual isolation of Yellow-eyed Penguin Megadyptes antipodes nests

SummaryThe concealed and widely dispersed nests of the rare and endangered Yellow-eyed Penguin Megadyptes antipodes, or “hoiho”, have been considered to reflect an essential requirement for the visual isolation of nest sites from conspecifics. However, this may be a consequence of selection for habitat features that provide protection from insolation, thereby minimising the risk of heat stress. To help improve the understanding of hoiho nesting requirements and the effectiveness of habitat restoration, we aimed to determine whether visual isolation from conspecifics or protection from insolation is the primary driver of hoiho nest site selection. We compared the mean maximum distance of visibility and the mean percentage insolation cover of active nests with randomly sampled unused sites in flax Phormium tenax and Hebe elliptica coastal scrub at Boulder Beach, and in coastal forest at Hinahina Cove, New Zealand, 2006–2007. Results of univariate tests and the evaluation of logistic regression models suggested that the amount of insolation cover was more important than visibility for hoiho nest site selection, particularly in flax and scrub. In addition, Spearman's correlations indicated that decreasing insolation cover significantly increased the visibility of nests in the forest habitat, and had a similar effect on inter-nest distance in flax. We infer that hoiho nest site selection and distribution are influenced primarily by the location and density of micro-habitat features (particularly within 1 m of the ground) that provide optimal protection from insolation, possibly along with other important features such as a firm backing structure. Strong selection for these features results in the typical but non-essential visual isolation of nest sites from conspecifics. Restoration of nesting habitats with a relatively high density and diversity of vegetation and solid structures within 1 m of the ground may eventually provide an optimal availability and quality of suitable nest sites.

Brent goose colonies near snowy owls: Internest distances in relation to breeding arctic fox densities

This study was conducted in 2005 near Medusa Bay (73 degrees 21' N, 80 degrees 32' E) and the delta of the Pyasina River (74 degrees 10' N, 86 degrees 45' E), northwest of the Taimyr Peninsula. It was shown that in the years when the numbers of the Arctic foxes are high, even though the lemming numbers are high as well, Brent geese nest considerably closer to owls' nests than in the years with low Arctic fox numbers. At values of the Arctic fox densities greater than one breeding pair per 20 km2, the factor of lemming numbers ceases to affect the distance between owl and geese nests. This distance becomes dependent on the Arctic fox density (numbers). When the Arctic fox density is greater than the pronounced threshold, the owl-Brent internest distance is inversely and linearly related to the Arctic fox density.

Colony spatial structure in polydomous ants: complimentary approaches reveal different patterns

Eusocial insects often live in colonies comprised of an extensive network of interconnected nests and estimating colony spatial structure and colony boundaries may be difficult, especially in cryptic, subterranean species. A combination of aggression assays and protein marking was used to estimate nest spatial distribution in field populations of the highly polydomous cornfield ant, Lasius neoniger. The estimates were first obtained via 1-on-1 aggression tests for workers collected from different nests within the research plots. The aggression tests were followed by mark-recapture field studies which utilized rabbit IgG protein. The ants were allowed to self-mark by feeding on sucrose solution spiked with the IgG protein. Colony spatial structure was detected by sampling ants from different nests and analyzing them for the presence of the marker using an ELISA test. Estimates based on aggression tests were substantially higher relative to those based on protein marking. The average colony size based on aggression tests was 2.0 ± 0.2 m2 and was significantly higher than the 1.1 ± 0.4 m2 estimate based on protein marking. The estimate based on protein marking was even lower, 0.2 ± 0.1 m2, when a Fluon-coated ring restricted ant feeding to the focal nest and prevented ants from other nests from feeding on the protein-marked sucrose. No significant correlation was detected between internest aggression and internest distance. Likewise, no correlation was detected between distance from the focal nest and the percentage of workers testing positive for the protein marker. The results show that both approaches have their own limitations, but their simultaneous use allows for a more accurate assessment of colony spatial structure. The advantages and limitations of each technique are discussed.

Home range, population density, and habitat utilization of the Sichuan Jay (Perisoreus internigrans)

We assessed habitat preference and population status of the Sichuan Jay (<i>Perisoreus internigrans</i>), a poorly known Chinese endemic bird, at two sites (Zhuoni and Jiuzhaigou) in the Qinghai-Tibetan plateau between 2001 and 2004. Mean group size was 3.8 jays. Each group occupied a mean home range of 42.0 ha during the breeding season, and the mean internest distance was 2.7 km. These data indicated that the jays used less than ten percent of the available habitats and occurred at an overall density of only 0.6 jays per km². Radio-tracked Sichuan Jays had a strong preference for mature montane coniferous forests and avoided areas dominated by shrubs, while the utilization of young conifers, grassland, and human residential habitat types did not differ significantly from the values expected from the home-range availabilities of these habitats generally.

Facultative nest patch shifts in response to nest predation risk in the Brewer’s sparrow: a “win-stay, lose-switch” strategy?

Facultative shifts in nesting habitat selection in response to perceived predation risk may allow animals to increase the survival probability of sessile offspring. Previous studies on this behavioral strategy have primarily focused on single attributes, such as the distance moved or changes in nesting substrate. However, nest site choice often encompasses multiple habitat elements at both the nest site and nest patch scales. We studied the within-season re-nesting strategy of a multi-brooded songbird, the Brewer's sparrow (Spizella breweri), to determine whether pairs utilized a "win-stay, lose-switch" decision rule with respect to inter-nest distance, nest substrate and/or nest patch characteristics in response to previous nest fate. Pairs moved sequential nest sites slightly farther following nest predation versus success. When inter-nest distance was controlled, however, pairs changed nest patch attributes (shrub height, potential nest shrub density) associated with probability of nest predation to a greater extent following nest predation than success. The strategy appeared to be adaptive; daily nest survival probability for previously depredated pairs increased with greater Euclidian habitat distances between attempts, whereas previously successful pairs were more likely to fledge second attempts when nest sites were similar to those of previous attempts. Our results suggest that nesting birds can use prior information and within-season plasticity in response to nest predation to increase re-nesting success, which may be a critical behavioral strategy within complex nest predator environments. Re-nesting site selection strategies also appeared to integrate multiple habitat components and inter-nest distances. The consideration of such proximate, facultative responses to predation risk may clarify often unexplained variation in habitat preferences and requirements.

Breeding Habitat Requirements and Selection by Olrog's Gull (Larus Atlanticus), A Threatened Species

AbstractWe studied habitat requirements and selection of Olrog's Gulls (Larus atlanticus) breeding at six colonies along 2,500 km of coastline in central Argentina that encompasses its entire distributional range. Colonies were located only on islands that ranged in size between 0.4 and 125.8 ha, and the islands' distance to the mainland varied from 0.12 to 16.7 km. Colonies ranged in size between 12 and 341 nests. In three of the colonies, gulls nested in subcolonies (range: 8–239 nests). They nested at relatively high densities, with a mean inter-nest distance of 0.66 ± 0.25 m. Logistic regression analysis to compare nest and random-site characteristics at each colony showed that Olrog's Gulls selected sites that were close to the high-tide line, at a lower height above sea level, far from available vegetation, and had lower vegetation cover over the nest. Olrog's Gulls showed a significant positive association with Kelp Gulls (L. dominicanus), an expanding generalist species that also nests in similar habitats. Current trends in coastal development, particularly in the Olrog's Gulls' main breeding grounds of southern Buenos Aires, indicate the urgent need for habitat-protection guidelines for this threatened species. Moreover, its breeding association with Kelp Gulls suggests a potential spatial conflict and highlights the need for increased monitoring and management actions.Selección y Requerimientos de Hábitat Reproductivo en Larus atlanticus, una Especie Amenazada

Nestmate discrimination in the queenless ponerine antDiacammasp. from Japan

AbstractWe examined the nestmate discrimination ability ofDiacammasp., an ant that reproduces by colony budding. We also tested for a relationship between internest distance and hostility. Hostility toward non‐nestmates was significantly stronger than that toward nestmates, suggesting thatDiacammasp. discriminates between nestmates and non‐nestmates. There was no significant correlation between internest hostility and internest distance, which indicates the absence of a “dear enemy” phenomenon in this species.

Intercolony Aggression Within and Among Local Populations of the Invasive Ant, &lt;I&gt;Myrmica rubra&lt;/I&gt; (Hymenoptera: Formicidae), in Coastal Maine

Myrmica rubra L. was introduced into New England in the early 20th century, and at present, has a patchy distribution in parts of northeastern North America, including records from 31 communities in Maine. M. rubra is highly polygynous, and colonies reproduce vegetatively, forming dense local populations where conditions are favorable. Using mobile nests and baited arenas in a series of field aggression bioassays, we tested patterns of internest tolerance within and among local populations on Mt. Desert Island, ME. We found that foragers originating from fragments of the same colony or from neighboring nests retained a high level of intraspecific tolerance over several months, whereas significant intercolony aggression among workers was present between colonies within the same local patch separated by approximately 10 m. Within populations, aggression score values were found to increase linearly with internest distance within a site. Aggression was highest between colonies from spatially different populations on the island and was higher still when nests were assayed against colonies at an off-island site 70 km away in Castine, ME. These data strongly suggest a multicolonial organization within and among local populations of M. rubra in parts of its introduced range. These findings contradict the loss of intraspecific aggression and unicolonial social structure over large geographic areas that have previously been observed in other invasive ant species, particularly Linepithema humile Mayr.

BREEDING HABITAT REQUIREMENTS AND SELECTION BY OLROG'S GULL (LARUS ATLANTICUS), A THREATENED SPECIES

Abstract We studied habitat requirements and selection of Olrog's Gulls (Larus atlanticus) breeding at six colonies along 2,500 km of coastline in central Argentina that encompasses its entire distributional range. Colonies were located only on islands that ranged in size between 0.4 and 125.8 ha, and the islands' distance to the mainland varied from 0.12 to 16.7 km. Colonies ranged in size between 12 and 341 nests. In three of the colonies, gulls nested in subcolonies (range: 8–239 nests). They nested at relatively high densities, with a mean inter-nest distance of 0.66 ± 0.25 m. Logistic regression analysis to compare nest and random-site characteristics at each colony showed that Olrog's Gulls selected sites that were close to the high-tide line, at a lower height above sea level, far from available vegetation, and had lower vegetation cover over the nest. Olrog's Gulls showed a significant positive association with Kelp Gulls (L. dominicanus), an expanding generalist species that also nests in similar...

Predicting the breeding success of large raptors in arid southern Africa: a first assessment

Raptors are often priorities for conservation efforts and breeding success is a target measure for assessing their conservation status. The breeding success of large raptors in arid southern Africa is thought to be higher in years of high rainfall. While this correlation has been found in several studies, it has not yet been shown for data from a wider geographical area. In conservation research, it is important to explore the differences between spatially-separated populations to estimate and to compare their conservation status, and to deduce specific management strategies. Using a theoretical approach, we develop a simplistic model to explain the breeding success-rainfall relationship in large African raptors at larger spatial scales. Secondly, we validate this model and we show that the inclusion of field data leads to consistent predictions. In particular, we recommend that the average size of the 'effective territory' should be included in the relationship between annual rainfall and breeding success of raptors in arid southern Africa. Accordingly, we suggest that breeding success is a function of precipitation and inter-nest distance. We present a new measure of territory quality depending on rainfall and territory size. We suggest that our model provides a useful first approach to assess breeding success in large raptors of arid southern Africa. However, we strongly emphasise the need to gather more data to further verify our model. A general problem in conservation research is to compare the status of populations assessed in different study areas under changing environmental conditions. Our simplistic approach indicates that this problem can be overcome by using a weighted evaluation of a target measure (i.e. breeding success), taking regional differences into account.

Conservation status and community structure of cliff-nesting raptors and ravens on the Cape Peninsula, South Africa

We detail the sizes, spatial distributions and trends in nest site selection of cliff-nesting raptor and raven populations resident in the mountains of the Cape Peninsula, South Africa. We also assess the conservation value of these populations to inform the future management of the newly-established Table Mountain National Park (TMNP), and examine the structure and interrelations within the raptor community. The combined number, dispersion and density of nests (n = 96 nests, mean inter-nest distance = 0.59km, density = 30.0 pairs/100km2) are comparable with those of high-density raptor populations studied elsewhere in Africa and the world. Densities of Verreauxs' Eagle Aquila verreauxii (n = 2, 12.01km, 0.6 pairs/100km2, respectively) and Jackal Buzzard Buteo rufofuscus (n = 9, 4.63, 2.8 pairs/100km2), are low, Rock Kestrel Falco rupicolus (n = 44, 1.75km, 13.8 pairs/100km2) high and Peregrine Falcon Falco peregrinus (n = 19, 3.13km, 5.9 pairs/100km2) exceptional, relative to populations of the same or similar species in other areas. There are no comparable data for White-necked Raven Corvus albicollis (n = 22, 3.22km, 6.9 pairs/100km2). All species combined, and Peregrines in particular, significantly prefer high cliffs from the available habitat. Peregrines generally dominate the other species, may affect cliff site selection and dispersion in the rest of the community, and tend to locate their nests close to those of White-necked Ravens. Numbers of Verreauxs' Eagle are lower than recent historical levels, perhaps because key prey populations are depleted. Any future recovery of this large predator could subtly affect the entire assemblage. This cliff-nesting raptor community is a significant asset of the TMNP, and should be considered in management decisions taken in the Park, particularly those concerning the regulation of leisure activities in the vicinity of nesting areas.

Factors affecting internest variation in the aggressiveness of a polygynous ant, Camponotus yamaokai

AbstractThe facultatively polygynous ant Camponotus yamaokai shows various degrees of internest hostility. We examined the relationship between aggressiveness and possible factors that affect the level of hostility, such as internest distance, numbers of queens and workers, and brood size. We found that the aggression level did not significantly correlate with these factors. Our study suggests that information on the colony genetic structure is important in understanding variation in the aggressiveness of polygynous colonies.

The relation between colony size, breeding density and ectoparasite loads of adult European bee-eaters (Merops apiaster)

The numbers of chewing lice were determined for adult bee-eaters and related to different measures of breeding density. Bee-eaters are infested by three species of chewing lice (Meropoecus meropis, Meromenopon meropis and Brueelia apiastri). Meropoecus meropis is the most common species and 94% of all adult bee-eaters were infested. This species also shows a significant variation between colonies, namely, infestation rate increases with colony size. Using different measures to describe colony size, a stepwise regression analysis showed that inter-nest distance is the best predictor for ectoparasite load. Average infestation rate per individual decreased significantly with increasing inter-nest distance. This relationship was even more pronounced for the maximum number of parasites found within a colony and with the variation in parasite load among members of a colony (controlling for number of breeding pairs). There was no difference in ectoparasite load between the sexes and no general patterns related to the position of the breeding site within the colony.

Spatial patterns of burrowing owl (Speotyto cunicularia) nests within black-tailed prairie dog (Cynomys ludovicianus) towns

The spatial patterns of burrowing owl (Speotyto cunicularia) nests in black-tailed prairie dog (Cynomys ludovicianus) towns were examined in the Nebraska panhandle during the spring and summer of 1989–1991. Because of higher nest densities (≥ 0.20 nests/ha) and internest distance requirements, it was not possible for owls to demonstrate patterns other than random in the smaller (&lt; 35 ha) prairie dog towns. In large prairie dog towns (&gt; 35 ha), burrowing owls were less dense (≤ 0.20 nests/ha), and choice of nest sites by pairs resulted in a clumped nest distribution. In prairie dog towns &lt; 35 ha, nearest neighbor distance was positively related to prairie dog town size, whereas no relationship was found between prairie dog town size and nearest neighbor distance for towns ≥ 35 ha. Burrow availability was not responsible for clumping. Ample burrows were available throughout the towns in 1990 and 1991. In 1991, two towns with clumped distributions of owls showed no differences in numbers of burrows around active owl nests and random burrows throughout the towns. Other possible explanations for clumping, including food availability and reduced predation risk, are discussed.

Limited Nutrients in a Dampwood Termite: Nest Preference, Competition and Cooperative Nest Defence

1. Prior laboratory manipulation of nitrogen availability indicated that monogamous pairs of Zootermopsis nevadensis (Isoptera: Termopsidae) exhibit cooperative behaviour patterns that increase nitrogen availability for reproduction and larval growth. I now present field evidence that reproductives preferentially seek and cooperatively defend nests rich in cambium-nitrogen. 2. Higher densities of newly flown adults disperse to logs with greater quantities of total cambium-nitrogen, but not to logs having greater amounts of wood xylem. Nest settlement occurs in an ideal free distribution in relation to cambium-nitrogen. The average nearest inter-nest distance between new pairs varies inversely with a log's average percentage nitrogen in the cambium layer