Male Nest Defense Research Articles

Plasticity, state-dependency, and individual consistency in Canada goose nest defense behavior

Animals are thought to adjust the intensity of their parental defense to fitness benefits associated with their current reproduction. They should be more defensive when they breed early in the season, when they produce more young, or as their young get older. Beyond these plastic changes, associations among traits could be explained by consistent among-individual differences. Separating the mechanisms at the origin of behavioral phenotypic variation is essential to understand the determinants and evolution of parental care. During four breeding seasons, we investigated whether variation in Canada goose (Branta canadensis) nest defense resulted from individual short-term plastic adjustments to reproductive stage within breeding seasons, plastic adjustments to brood value across breeding seasons, or from long-term among-individual differences. We thus estimated the among- and within-individual relationships between nest defense, clutch size, and laying date. Female and male nest defense behaviors were highly repeatable in time (R = 0.72 and 0.67 on the short term). At the among-individual level, we found no significant association between female nest defense and life history traits, but the more defensive males were mated with the more fecund females. Female and male nest defense was not adjusted to annual variation in laying date nor in clutch size. However, females adjusted their nest defense within each breeding season and became more defensive when approaching egg hatching. Thus, Canada goose nest defense behavior is partly explained by plastic adjustments, but also by consistent among-individual differences which indicate the evolutionary potential of nest defense behavior. An association between traits at the phenotypic level can be partitioned into association at the among- and within-individual levels. This allows to better understand covariation of traits resulting from both among-individual differences and phenotypic plasticity. We observed 141 Canada goose pairs to identify what affected the intensity of their nest defense behavior. We found that geese were very consistent in their nest defense behavior and that female fecundity was related to male personality. Females also became more defensive as their young got older. Analyzing different sources of variation in parental behaviors enables a better understanding of their evolution. Our study also demonstrates the importance of studying nest defense in both sexes even in species where only females incubate eggs, as both sexes can invest in nest defense.

The Role of Agonistic Sounds in Male Nest Defence in the Painted Goby Pomatoschistus pictus

AbstractAnimals often vocalize during territorial challenges as acoustic signals may indicate motivation and fighting ability and contribute to reduce aggressive escalation. Here, we tested the function of agonistic sounds in territorial defence in the painted goby. Pomatoschistus pictus, a small vocal marine fish that defends nests during the breeding season. We first measured the number of times a male approached, avoided, explored, entered and exited two unattended nests associated with either conspecific agonistic sounds or a control: silence or white noise. Acoustic stimuli were played back when the male approached a nest. In a second experimental set, we added visual stimuli, consisting of a conspecific male in a small confinement aquarium near each nest. Even though we found no effect of the visual stimuli, the sound playbacks induced similar effects in both experimental conditions. In the sound vs. silence treatment, we found that when males approached a nest, the playback of conspecific sounds usually triggered avoidance. However, this behaviour did not last as in longer periods males visited nests associated with agonistic sounds more often than silent ones. When the control was white noise, we found no significant effect of the playback treatment in male behaviour. Although we cannot exclude the possibility that other sounds may dissuade nest occupation, our results suggest that agonistic sounds act as territorial intrusion deterrents but are insufficient to prevent nest intrusion on their own. Further studies are needed to test the significance of sound production rate, spectral content and temporal patterns to deter territorial intrusion in fish.

Repeatable nest defense behavior in a wild population of Eastern bluebirds (Sialia sialis) as evidence of personality

Consistent individual differences in behavior, or personality, have been demonstrated in a variety of species other than humans, including mammals, birds, and invertebrates. Behavioral consistency has been shown to affect dispersal, foraging, exploration, and antipredator responses, which may have an impact on parental and offspring survival. Despite increasing research in behavioral consistency, the repeatability of nest defense behavior has rarely been assessed in wild bird populations. Furthermore, previous studies investigating nest defense behavior have utilized laboratory studies or mounted predators to elicit defensive behavior. It is important to assess personality in wild populations to fully understand the fitness consequences of behavioral consistency across natural contexts and to utilize live predators or competitors for accurate assessment of defensive behavior. We used an ecologically relevant, live, invasive, nest site competitor, the house sparrow (Passer domesticus), to elicit nest defense behavior in a wild population of Eastern bluebirds (Sialia sialis) to determine if nest defense behavior is repeatable within and between years for males and females (males: 2009, N = 17; 2010, N = 18; both years, N = 9. Females: 2009, N = 22; 2010, N = 15; both years, N = 11). We also determined if individual behavior changes as a function of season, parental age, brood size, or the number of house sparrows around the nest site. We found that females demonstrated repeatable behavior both within and between years. Male nest defense behavior was only repeatable in 1 year and was influenced by season in the other year. Parental age, brood size, and the number of house sparrows around the nest site did not affect nest defense behavior. We conclude that Eastern bluebirds demonstrate consistent nest defense behavior, or personality, although males are more plastic than females.

Male Rock Sparrow (Petronia petronia) Nest Defence Correlates with Female Ornament Size

AbstractWe investigated the relationship between male nest defence and female breast patch size in an alpine population of rock sparrow (Petronia petronia) in northern Italy. We presented a mounted weasel (Mustela nivalis), a common nest predator, to 28 pairs breeding in nest boxes, with 12–13‐d‐old nestlings, and measured the intensity of male and female defence reaction. We measured the frequency of attack flights, intensity of alarm calling and total time spent in view, and then combined these for each individual, in a single defence factor by principal component analysis. All the females arrived to defend the nest while only 21 males arrived, and females defended the nest more intensely than males. We analysed, by stepwise regression, the relationship of male defence factor to female behaviour and phenotype (breast patch size, a measure of quality) and brood properties (size, mass, phenology). Male defence factor was significantly related only to female breast patch size. We argue that male rock sparrows apparently make parental investment decisions according to their mate's quality, and examine possible alternative hypotheses.

Bilateral symmetry as an indicator of male quality in red-winged blackbirds: associations with measures of health, viability, and parental effort

Recent evidence suggests that in many animal taxa, males characterized by low levels of bilateral asymmetry realize a mating advantage. The mechanisms responsible are poorly understood, but there is much interest in the possibility that symmetry reflects aspects of underlying individual quality and that females use symmetry as a criterion for mate selection. We used data assembled from a 5-year field study of red-winged blackbirds (Agelaixu phoeniceus) to explore the possibility that symmetry provides females with information regarding the quality of potential mates. Asymmetry measures made on a variety of paired characters, whether considered alone or in combination, were generally unrelated to the nutritional status (i.e., body condition) of individual males. Similarly, we found no differences in asymmetry levels exhibited by males infected and those uninfected with avian hematozoa. Composite (i.e., multicharacter) asymmetry was related to infestation by two broad classes of ectoparasites (hematophagous mites and ischnoceran lice), but these relationships were weak and opposite to those expected under the male quality hypothesis. Direct assessment of male viability based on annual return to the breeding grounds generally did not support the prediction that symmetrical males have higher survival prospects, nor was symmetry predictive of male nest defense, the primary form of paternal care in our study population. Collectively, these results are inconsistent with the proposal that symmetry reflects high mate quality, which in turn suggests that, in red-winged blackbirds, the potential for female choice based on this aspect of morphology is probably weak or nonexistent.

Determinants of Nesting Success in the Pumpkinseed (Lepomis gibbosus): A Comparison of Two Populations under Different Risks from Predation

location, and water chemistry but with different fish communities. Ranger Lake had well-established populations of smallmouth and largemouth bass and few planktivorous fish, whereas Mouse Lake had no piscivores and many planktivorebenthivores capable of consuming pumpkinseed eggs and larvae. Both lakes had well-established pumpkinseed populations, but nesting success was significantly higher in Ranger Lake. The influences of environmental factors (nesting substratum and depth, temperature, solar radiation, precipitation, and wind velocity) on nesting success were investigated, and only wind-induced water turbulence was important. Although wind events were associated with significant amounts of nest destruction, the effects were the same in both lakes. Nest attacks and male nest defense were higher in Mouse Lake, particularly at night. These attacks came from the dense populations of golden shiners found at Mouse Lake and resulted in the loss of many pumpkinseed nests. We conclude that a predatorinduced cascade indirectly influenced nesting success. At Mouse Lake, piscivores were rare, planktivore-benthivore nest predators were abundant, nest-specific behavioral interactions were numerous and nesting success was low. At Ranger Lake, large piscivores were abundant, planktivore-benthivore numbers were low, and nesting success was high.

Nest defence as shareable paternal care in red-winged blackbirds

One of the costs to female birds of mating polygynously is having to share the parental care provided by their mate. Nest defence, however, is one form of paternal care that females mated to the same male should be able to share. In this study there was no difference in the defence of primary and secondary nests by male red-winged blackbirds, Agelaius phoeniceus. Nests that were provisioned by males were not defended more aggressively than nests that were not provisioned. Nests that were successful had been defended more aggressively by males than those that failed, indicating that male nest defence is valuable to females. These results suggest that male nest defence is entirely shareable, in contrast to a recent study that showed males preferentially defended nests of primary females ( Knight & Temple, Condor, 1988 , 90, 193–200). Although the study design used here more realistically reflects natural nest defence (males had to defend one nest at a time rather than having to choose which of two nests to defend), it does not explain why males preferentially defended certain nests when forced to make a choice but not when defending nests one at a time.

Cavity Nesting and Male Nest Defense by the Ornate Minnow, Codoma ornata (Pisces: Cyprinidae)

Le nid est un systeme de defense du nid par les mâles sont decrits chez C.o. La relation parmi les cyprinides presentant un nid et une defense du nid par le mâle est discute

Is Courtship Intensity a Signal of Male Parental Care in Red-Winged Blackbirds (Agelaius phoeniceus)?

Abstract We studied Red-winged Blackbird (Agelaius phoeniceus) behavior in marsh and prairie habitats to determine whether courting males provide cues of their nest defense, whether females prefer males that defend nests vigorously, and whether male nest defense affects nest success. We found no evidence that courtship behavior provides cues of male nest defense, or that females prefer males that court intensely. We found evidence that females nesting in marshes prefer males that defend nests intensely, but no evidence that intensely defending males in the prairie habitat achieve high nest success. We found differences, however, between marsh and prairie habitats that suggest a coarse-grained relationship between male parental quality and female choice of mate in this species.

The influence of microtines on polygyny, productivity, age, and provisioning of breeding Northern Harriers: a 5-year study

Breeding Northern Harriers, Circus cyaneus, and their principle prey, the vole Microtus pennsylvanicus, underwent synchronous fluctuations in New Brunswick between 1980 and 1984. Microtines were abundant in 1980 and 1983 and were significantly tracked by the number of nesting harriers (r = 0.90), the number of polygynous males (r = 0.89), the number of harem females (r = 0.90), and the mean clutch size (r = 0.94), but not the reproductive success of successful females (r = 0.72). Male nest defence likewise exhibited a strong relationship (r = 0.99, n = 3) with prey abundance, but nest predation did not. An unexpected association with prey abundance was the greater proportion of young females (≤ 2 years) breeding at vole lows; the reverse was true for yearling males. Young females that did breed at vole highs were significantly more productive than were old females breeding at highs. The difference arose principally through nest predation. Successful females also consistently reared significantly greater proportions of their hatchlings when voles were increasing than when they were decreasing. Our results suggest that New Brunswick harriers were affected by prey fluctuations in most aspects of their reproduction and population dynamics. Significant correlations between male food provisioning rates and clutch size and reproductive success over 3 years provide a proximate mechanism through which fecundity may vary annually. They may also provide a proximate pathway mediating for polygyny.

Hummingbirds Feeding from Exudates on Diseased Scrub Oak

971) suggested that this represented a use of song selected to acquire male nest defense. In this case, as in the Black-headed Grosbeak, such deceptive behavior would be adaptive since both parties would ultimately benefit by the female's singing and the male's reaction to it, i.e., the bluebird nest is defended against a possible predator and the eggs or young of the grosbeak are not left unprotected when the female leaves the nest. I thank Keith L. Dixon for his assistance in this study. I also thank Susan Smith and an anonymous reviewer for helpful suggestions on the manuscript. This study was supported by grants from The Frank M. Chapman Memorial Fund of The American Museum of Natural History and from Sigma Xi.