Parental-care responses by yellow warblers (Dendroica petechia) to simultaneous manipulations of food abundance and brood size

1998 ◽  
Vol 76 (5) ◽  
pp. 916-924 ◽  
Author(s):  
G A Lozano ◽  
R E Lemon

Theoretical models view biparental care as a state of equilibrium that can be maintained only when the amount of parental care provided by one parent depends on the amount provided by its mate. According to these models, biparental care results when a decrease in the contribution of one parent is partially, but not completely, compensated for by an increase in the contribution of the other parent. Furthermore, this equilibrium state can only be stable if any other external factor affects male and female effort equally. We used yellow warblers (Dendroica petechia) to examine whether changes in brood size and food abundance affect the parental contributions of the sexes equally. Supplemental food did not affect parental care by either sex, but brood size did. Both males and females provided more to larger broods, and in large broods only, their provisioning rates increased with nestling age. Parental effort per nestling was similar in the two sexes, being higher for smaller broods and increasing with nestling age. Based on brood biomass, parental effort was greater for smaller broods, and decreased with nestling age in females only. Therefore, in agreement with current models of the maintenance of biparental care, the effects of brood size and nestling age on parental care did not differ significantly between the sexes. Nonetheless, data from other species and theory indicate that the costs and benefits of providing parental care differ between the sexes, so it is unlikely that biparental care can be maintained solely by a partial compensation response.

2021 ◽  
Author(s):  
Pascual LÓPEZ-LÓPEZ ◽  
Arturo M PERONA ◽  
Olga EGEA-CASAS ◽  
Jon ETXEBARRIA MORANT ◽  
Vicente URIOS

Abstract Cutting-edge technologies are extremely useful to develop new workflows in studying ecological data, particularly to understand animal behaviour and movement trajectories at the individual level. Although parental care is a well-studied phenomenon, most studies have been focused on direct observational or video recording data, as well as experimental manipulation. Therefore, what happens out of our sight still remains unknown. Using high-frequency GPS/GSM dataloggers and tri-axial accelerometers we monitored 25 Bonelli’s eagles (Aquila fasciata) during the breeding season to understand parental activities from a broader perspective. We used recursive data, measured as number of visits and residence time, to reveal nest attendance patterns of biparental care with role specialization between sexes. Accelerometry data interpreted as the Overall Dynamic Body Acceleration, a proxy of energy expenditure, showed strong differences in parental effort throughout the breeding season and between sexes. Thereby, males increased substantially their energetic requirements, due to the increased workload, while females spent most of the time on the nest. Furthermore, during critical phases of the breeding season, a low percentage of suitable hunting spots in eagles’ territories led them to increase their ranging behaviour in order to find food, with important consequences in energy consumption and mortality risk. Our results highlight the crucial role of males in raptor species exhibiting biparental care. Finally, we exemplify how biologging technologies are an adequate and objective method to study parental care in raptors as well as to get deeper insight into breeding ecology of birds in general.


2017 ◽  
Author(s):  
Ádám Z. Lendvai ◽  
Çağlar Akçay ◽  
Mark Stanback ◽  
Mark F. Haussmann ◽  
Ignacio T. Moore ◽  
...  

AbstractBiparental care presents an interesting case of cooperation and conflict between unrelated individuals. Several models have been proposed to explain how parents should respond to changes in each other’s parental care to maximize their own fitness, predicting no change, partial compensation, or matching effort as a response. Here, we present an experiment in tree swallows (Tachycineta bicolor) in which we increased the parental care of females by presenting them, but not their mates, with additional nestling begging calls using automated playbacks. We performed this experiment in two populations differing in future breeding opportunities and thus the intensity of conflict over current parental care. We found that in response to a temporary increase in female parental effort, males in the northern population with lower sexual conflict matched the increased effort, whereas males in the southern population did not. We also found that increases in parental care during playbacks were driven by the females (i.e., females initiated the increased effort and their mates followed them) in the northern population but not the southern population. These results support the idea that with incomplete information about the brood value and need, cues or signals from the partner might become important in coordinating parental care.


The Auk ◽  
1987 ◽  
Vol 104 (4) ◽  
pp. 688-693 ◽  
Author(s):  
Martin Schindler ◽  
Jürg Lamprecht

Abstract Positive correlations of brood size with some parental activities [vigilance (in females), approaching young (in males and females), and attack (in males)] and a negative correlation of female feeding time with brood size were found in a sample of 23 semicaptive Bar-headed Goose (Anser indicus) families. Detailed examination of these correlations suggests that some components of parental care in geese represent "shared parental investment" (Lazarus and Inglis 1978, 1986). The benefits of parental care are divided among the offspring, so that in precocial birds, as in altricial birds, clutch size may be adapted to selection pressures that act after the young hatch.


1989 ◽  
Vol 67 (2) ◽  
pp. 268-273 ◽  
Author(s):  
Michael V. Studd ◽  
Raleigh J. Robertson

Individual male Yellow Warblers (Dendroica petechia) exhibit differences in their level of parental investment, which correlate with the amount of brown streaking on the breast. We tested two alternative hypotheses to explain these patterns. The age effect hypothesis proposes that the variation in plumage and parental behaviour is an effect of differences in male age. This was tested by analyzing the nest visit rates and plumage scores of banded males present in the study in more than 1 year. The age effect hypothesis is rejected because there was no evidence of significant within-male variation due to increasing age, nor of any consistent directional change in either parental effort or plumage pattern between years. The territory quality hypothesis proposes that the quality of territory occupied has an important proximate influence on male parental effort. By observing the same territories over different years we were able to compare nest visit rates of different males with different plumage scores while holding the effect of territory quality constant. Analysis of variance revealed that male plumage rank had a highly significant effect on nest visit rate, while the effect of territory occupied was not significant. Rejection of these two alternative hypotheses provides further support for the hypothesis that phenotypically different males are using alternative and irreversible lifetime reproductive strategies.


2019 ◽  
Vol 30 (4) ◽  
pp. 1062-1068 ◽  
Author(s):  
Marwa M Kavelaars ◽  
Luc Lens ◽  
Wendt Müller

Abstract In species with biparental care, individuals only have to pay the costs for their own parental investment, whereas the contribution of their partner comes for free. Each parent hence benefits if its partner works harder, creating an evolutionary conflict of interest. How parents resolve this conflict and how they achieve the optimal division of parental tasks often remains elusive. In this study, we investigated whether lesser black-backed gulls (Larus fuscus) divide parental care during incubation equally and whether this correlates with the extent of vocalizations between pair-members during incubation. We then investigated whether pairs showing more evenly distributed incubation behavior had a higher reproductive success. To this end, we recorded incubation behavior and vocalizations for 24-h time periods. Subsequently, we experimentally increased or decreased brood sizes in order to manipulate parental effort, and followed offspring development from hatching till fledging. Although incubation bouts were, on average, slightly longer in females, patterns varied strongly between pairs, ranging from primarily female incubation over equal sex contributions to male-biased incubation. Pairs contributing more equally to incubation vocalized more during nest relief and had a higher reproductive output when brood sizes were experimentally increased. Thus, vocalizations and a more equal division of parental care during incubation may facilitate higher levels of care during the nestling period, as suggested by a greater reproductive success when facing high brood demand, or they indicate pair quality.


The Auk ◽  
1988 ◽  
Vol 105 (1) ◽  
pp. 149-160 ◽  
Author(s):  
David F. Westneat

Abstract Levels of parental care by male Indigo Buntings (Passerina cyanea) were predicted to be lower and the tendency to pursue extrapair matings greater when (1) the opportunity of additional matings (extrapair copulations) was high, (2) the male was cuckolded, and (3) the clutch or brood size was small. Observations of male care revealed that approximately 10% of all males fed nestlings at least once, whereas more than 30% fed fledglings. Males in their first breeding season were never seen feeding young. Males made more trips off their territories when females were fertilizable on nearby territories, but other measures of parental care (feeding young and time spent within 10 m of nest) were not affected. Cuckolded males (known through genetic analyses of parents and offspring) tended to feed young less often, but forayed off their territories significantly less than apparently uncuckolded males. Finally, males with small clutches or broods gave slightly, but not significantly, less care than males with large clutches or broods. These results suggest that the relationship between mating effort and parental effort is complicated by the presence of extrapair copulations as a type of mating effort, and that factors not included in current theory on parental care might influence a male's parental care.


Sign in / Sign up

Export Citation Format

Share Document