Genetic monogamy in single-male groups of acorn woodpeckers, Melanerpes formicivorus

1995 ◽  
Vol 4 (6) ◽  
pp. 765-770 ◽  
Author(s):  
J. DICKINSON ◽  
J. HAYDOCK ◽  
W. KOENIG ◽  
M. STANBACK ◽  
F. PITELKA
The Condor ◽  
2007 ◽  
Vol 109 (2) ◽  
pp. 334-350
Author(s):  
Walter D. Koenig ◽  
Justyn T. Stahl

Abstract Acorn Woodpeckers (Melanerpes formicivorus) at Hastings Reservation in central coastal California exhibit a bimodal peak in annual breeding activity. One peak occurs in spring during which the majority of breeding takes place, while a second is centered in late August as the new acorn crop matures. These latter nests are mostly initiated in late summer but often do not fledge until at least late September and are thus referred to here as ‘fall’ nests. Fall nests occur in about one-third of all years, taking place when the acorn crop is large and summer temperatures are relatively high. Fledglings from fall nests constitute 4.3% of the population's total productivity and survive and recruit to the population at levels comparable to spring fledglings. Fall nesting is less likely in groups in which either the male or female breeding adults have undergone a change from the prior year, but groups are otherwise indistinguishable. Ecologically, fall nesting is closely tied to the acorn crop and thus to breeding success in the following, rather than the prior, spring. Among North American terrestrial birds in general, fall breeding has been reported in 16% of all species and is significantly more common among residents and colonially nesting species, in which the frequency exceeds 25%. Furthermore, fall nesting is likely to have been underreported in the literature. Thus, this phenomenon is at least an irregular part of the breeding biology of a substantial fraction of North American birds and should be considered a possibility in population studies of temperate-zone species. This is especially true given that fall nesting is likely to increase as global warming takes place.


2020 ◽  
Vol 31 (5) ◽  
pp. 1257-1265 ◽  
Author(s):  
Michael A Pardo ◽  
Eric L Walters ◽  
Walter D Koenig

Abstract Triadic awareness, or knowledge of the relationships between others, is essential to navigating many complex social interactions. While some animals maintain relationships with former group members post-dispersal, recognizing cross-group relationships between others may be more cognitively challenging than simply recognizing relationships between members of a single group because there is typically much less opportunity to observe interactions between individuals that do not live together. We presented acorn woodpeckers (Melanerpes formicivorus), a highly social species, with playback stimuli consisting of a simulated chorus between two different individuals, a behavior that only occurs naturally between social affiliates. Subjects were expected to respond less rapidly if they perceived the callers as having an affiliative relationship. Females responded more rapidly to a pair of callers that never co-occurred in the same social group, and responded less rapidly to callers that were members of the same social group at the time of the experiment and to callers that last lived in the same group before the subject had hatched. This suggests that female acorn woodpeckers can infer the existence of relationships between conspecifics that live in separate groups by observing them interact after the conspecifics in question no longer live in the same group as each other. This study provides experimental evidence that nonhuman animals may recognize relationships between third parties that no longer live together and emphasizes the potential importance of social knowledge about distant social affiliates.


2019 ◽  
Author(s):  
Hana Londoño Oikawa ◽  
Paulo C. Pulgarín-R

ABSTRACTAbiotic and biotic factors are known to be key in limiting the geographical distribution of species. However, our understanding on the influence of habitat heterogeneity on ecological interactions and behavior in tropical animals is limited. We studied groups of Acorn Woodpeckers (Melanerpes formicivorus flavigula) in urban and rural areas in northern South America to understand how habitat and resource requirements (food storage structures) influences patterns of distribution across the Aburrá Valley, in the northern area of the Central Andes of Colombia. Using focal observations of 10 different groups over nearly a two-year period, we estimated territory size, habitat use, and described the use and presence of granaries. We found that territory size, tree diversity, and the use of granaries varied among groups. Accordingly, Acorn Woodpeckers use a wide variety of tree species to make cavities, to feed and to build granaries for social interactions. Our study supports the hypothesis that Acorn Woodpeckers do not rely on the Colombian Oak (Quercus humboldtiiBonpl.) for feeding, nesting or foraging in the Aburrá Valley, and that the construction of granaries to store food is present in urban populations, despite the lack of strong seasonal changes in tropical areas. We suggest that the distribution of the Acorn Woodpecker in our study area is strongly associated with one particular species of tree,Albizia carbonariaBritton, and the behavior of granaries construction might be hardwired in this species for the maintenance and cohesion of family groups.


Oecologia ◽  
2010 ◽  
Vol 166 (1) ◽  
pp. 187-196 ◽  
Author(s):  
Douglas G. Scofield ◽  
Victor Ryan Alfaro ◽  
Victoria L. Sork ◽  
Delphine Grivet ◽  
Edith Martinez ◽  
...  

2018 ◽  
Vol 285 (1882) ◽  
pp. 20181017 ◽  
Author(s):  
Michael A. Pardo ◽  
Emilee A. Sparks ◽  
Tejal S. Kuray ◽  
Natasha D. Hagemeyer ◽  
Eric L. Walters ◽  
...  

According to the social intelligence hypothesis, understanding the cognitive demands of the social environment is key to understanding the evolution of intelligence. Many important socio-cognitive abilities, however, have primarily been studied in a narrow subset of the social environment—within-group social interactions—despite the fact that between-group social interactions often have a substantial effect on fitness. In particular, triadic awareness (knowledge about the relationships and associations between others) is critical for navigating many types of complex social interactions, yet no existing study has investigated whether wild animals can track associations between members of other social groups. We investigated inter-group triadic awareness in wild acorn woodpeckers ( Melanerpes formicivorus ), a socially complex group-living bird. We presented woodpeckers with socially incongruous playbacks that simulated two outsiders from different groups calling together, and socially congruous playbacks that simulated two outsiders from the same group calling together. Subjects responded more quickly to the incongruous playbacks, suggesting that they were aware that the callers belonged to two different groups. This study provides the first demonstration that animals can recognize associations between members of other groups under natural circumstances, and highlights the importance of considering how inter-group social selection pressures may influence the evolution of cognition.


2015 ◽  
Vol 45 (8) ◽  
pp. 1113-1120 ◽  
Author(s):  
Devin E. McMahon ◽  
Ian S. Pearse ◽  
Walter D. Koenig ◽  
Eric L. Walters

Forest communities change in response to shifting climate, changing land use, and species introductions, as well as the interactions of established species. We surveyed the oak (Quercus L. spp.) community and Acorn Woodpecker (Melanerpes formicivorus (Swainson, 1827)) population within 230 ha of oak forest and savanna in central coastal California in 1979 and 2013 to assess demographic changes over a timescale relevant to mature oaks. Overall, percent canopy cover increased, particularly where coast live oak (Quercus agrifolia Née) and California black oak (Quercus kelloggii Newberry) were most abundant. The density of stems of Q. agrifolia increased, whereas the density of stems and basal area of valley oak (Quercus lobata Née), a species favored by Acorn Woodpeckers, decreased. The number of Acorn Woodpeckers and woodpecker territories increased over the study period, coincident with the increase in percent canopy cover; however, these increases were not related spatially. Instead, increased acorn production associated with broad-scale canopy growth likely more than compensated for the loss of Q. lobata. Our findings suggest that forests in this area are becoming denser and savanna is becoming more open, which so far has supported an increase in the Acorn Woodpecker population, despite potential habitat loss if Q. lobata continues to decline.


2021 ◽  
Vol 288 (1957) ◽  
pp. 20210579
Author(s):  
Sahas Barve ◽  
Christina Riehl ◽  
Eric L. Walters ◽  
Joseph Haydock ◽  
Hannah L. Dugdale ◽  
...  

Cooperative breeding strategies lead to short-term direct fitness losses when individuals forfeit or share reproduction. The direct fitness benefits of cooperative strategies are often delayed and difficult to quantify, requiring data on lifetime reproduction. Here, we use a longitudinal dataset to examine the lifetime reproductive success of cooperative polygamy in acorn woodpeckers ( Melanerpes formicivorus ), which nest as lone pairs or share reproduction with same-sex cobreeders. We found that males and females produced fewer young per successful nesting attempt when sharing reproduction. However, males nesting in duos and trios had longer reproductive lifespans, more lifetime nesting attempts and higher lifetime reproductive success than those breeding alone. For females, cobreeding in duos increased reproductive lifespan so the lifetime reproductive success of females nesting in duos was comparable to those nesting alone and higher than those nesting in trios. These results suggest that for male duos and trios, reproductive success alone may provide sufficient fitness benefits to explain the presence of cooperative polygamy, and the benefits of cobreeding as a duo in females are higher than previously assumed. Lifetime individual fitness data are crucial to reveal the full costs and benefits of cooperative polygamy.


Behaviour ◽  
1985 ◽  
Vol 95 (3-4) ◽  
pp. 290-312 ◽  
Author(s):  
Ronald L. Mumme ◽  
Alan De Queiroz

AbstractAcorn woodpeckers (Melanerpes formicivorus) are communal breeders that live in permanently territorial family groups of 2-15 individuals. All group members participate in several forms of cooperative behaviour, which we define as the investment of resources in a common interest shared by other group members (CHASE, 1980). Acorn woodpecker group interests include the caching of acorns in a specialized storage tree (the granary), maintenance of the granary, and defence of the granary against intra- and interspecific intruders. Because of a strong positive relationship between the availability of stored acorns and group reproductive success, investments in acorn storage, granary maintenance, and granary defence have a direct positive effect on the individual fitness of breeders. Non-breeding helpers, however, do not realize a direct reproductive reward, and therefore profit less directly from investment in these forms of cooperative behaviour. Thus, we predicted that breeders should invest more heavily in cooperative behaviour than should helpers. The prediction was upheld: for nearly every form of cooperative behaviour examined, breeders contribute significantly more than do helpers. On the other hand, while established breeders only rarely intrude on neighbouring territories, nonreproductive helpers frequently do so. These dispersal "forays" constitute attempts by helpers to locate ecologically restricted breeding vacancies. The effect that group size has on individual contributions to cooperative behaviour is unclear. Individual rates of acorn storage decrease significantly with increasing group size, but granary attendance and granary maintenance do not. Male and female acorn woodpeckers do not differ in their contributions to acorn storage, granary maintenance, or interspecific defence. Females, however, play a significantly greater role in intraspecific defence because of a female-biased intruder sex ratio and sex-specific defensive behaviour.


2020 ◽  
Vol 31 (5) ◽  
pp. 1120-1128 ◽  
Author(s):  
Michael A Pardo ◽  
Casey E Hayes ◽  
Eric L Walters ◽  
Walter D Koenig

Abstract In species with long-term social relationships, the ability to recognize individuals after extended separation and the ability to discriminate between former social affiliates that have died and those that have left the group but may return are likely to be beneficial. Few studies, however, have investigated whether animals can make these discriminations. We presented acorn woodpeckers (Melanerpes formicivorus), a group-living, cooperatively breeding bird, with playbacks of current group members, former group members still living nearby, former group members that had died or left the study area, and familiar nongroup members. Subjects responded more quickly to the calls of nongroup members than to the calls of current group members or former group members still living in the study area but did not discriminate between nongroup members and former group members that had died or disappeared. This suggests that acorn woodpeckers can vocally recognize both current group members and former group members that have dispersed to nearby groups and that they either forget former group members that no longer live in the vicinity or classify them differently from former group members that still live nearby. This study suggests an important role for vocal recognition in maintaining valuable relationships with social affiliates postdispersal.


Sign in / Sign up

Export Citation Format

Share Document