The Influence of Food Abundance on Nest-Box Occupancy and Territory Size in the Tree Swallow, a Species That Does Not Defend a Feeding Territory

The Condor ◽  
2012 ◽  
Vol 114 (3) ◽  
pp. 595-605 ◽  
1981 ◽  
Vol 59 (9) ◽  
pp. 1801-1809 ◽  
Author(s):  
Lawrence M. Dill ◽  
Ronald C. Ydenberg ◽  
Alex H. G. Fraser

Feeding territory size and potential food abundance were measured simultaneously in a field population of juvenile (40–50 mm) coho salmon. Territory size was inversely related to the density of benthic food on the territory, as predicted from an energy-based model of territoriality. The relationship between the abundance of drift food and territory size was in the predicted direction, but was not significant. Territories were also smaller where intruder pressure was higher, but intrusion rate and food abundance were not directly correlated. Therefore, the effect of food abundance on territory size was not caused indirectly by attraction of nonterritorial fish to areas where food was abundant. In the laboratory, the distance from which a resident coho attacked an approaching model intruder increased asymptotically with hunger. The fish therefore appear to possess an appropriate behavioural mechanism (tactic) to adjust territory size to local food abundance.


The Auk ◽  
1986 ◽  
Vol 103 (4) ◽  
pp. 694-700 ◽  
Author(s):  
Hisashi Nagata

Abstract Morphological and territorial factors that influence female mate choice were examined in the monogamous Middendorff's Grasshopper-Warbler (Locustella ochotensis) on an islet near Fukuoka, Japan. I assumed that pairing date corresponded with female mate choice. Pairing date was correlated with both territory size and food abundance but was not correlated with selected morphological characteristics of males. Territorial quality was assumed to be correlated with territory size because preferable food resources and nest sites were distributed randomly. I conclude that female mate choice was influenced by territory quality rather than by the morphological characteristics of males.


Behaviour ◽  
1999 ◽  
Vol 136 (10-11) ◽  
pp. 1347-1363 ◽  
Author(s):  
James W.A. Grant ◽  
Jason Praw

AbstractModels of optimal territory size are usually tested only by demonstrating that territory size is inversely related to food abundance or intruder number. The most fundamental predictions of the models, however, have rarely been tested: i.e. the fitness of the defender is a function of territory size and the optimal territory is one of intermediate size. We tested these predictions by measuring the growth rate of large convict cichlids (Archocentrus nigrofasciatus, formerly Cichlasoma nigrofasciatum) while defending food patches against smaller intruders over a 10-day period. Food patches differed in area by more than two orders of magnitude. We manipulated food abundance so that it increased with patch size in a decelerating way. As assumed, the realized benefits of defence (weight of food eaten by the defender) and the costs of defence (chase rate and chase radius) both increased in a decelerating way with increasing patch area. As predicted, the growth rate of the defender first increased and then decreased with increasing patch size. The initial increase in defender growth rate with increasing patch size was related to an increase in food eaten, but the decrease in growth rate for fish defending the largest patches was related to the costs of defence. Fish defending large patches had a low growth efficiency, apparently because of the social stress caused by intruders in their territories. Taken together, these results support the assumptions and predictions of optimal territory size models.


2020 ◽  
Vol 134 (3) ◽  
pp. 217-221
Author(s):  
Kestrel V.B. DeMarco ◽  
Paul R. Martin

The ecology of Pustulated Burying Beetle (Nicrophorus pustulatus, Coleoptera: Silphidae) appears distinct among Nicrophorus species, with evidence of it parasitizing snake eggs and foraging primarily above the ground and into the forest canopy. Here we document an extension of its aberrant ecology and behaviour: a case of N. pustulatus burying 2-day-old live and dead nestlings of Tree Swallow (Tachycineta bicolor, Passeriformes: Hirundinidae) under the nest, behaviour consistent with the early stages of breeding in N. pustulatus. Based on different levels of decomposition, we suspect that N. pustulatus responded to one dead swallow nestling in the brood of five and went on to bury all of the nestlings at the bottom of the nest box. The observation provides the first evidence, to our knowledge, of Nicrophorus burying live vertebrates.


2021 ◽  
Vol 8 (11) ◽  
Author(s):  
Tore Slagsvold ◽  
Karen L. Wiebe

Many species of birds incorporate feathers into their nest as structural support and to insulate the eggs or offspring. Here, we investigated the novel idea that birds reduce the risk of nest usurpation by decorating it with feathers to trigger a fear response in their rivals. We let prospecting birds choose between a dyad of nest-boxes in the wild, both containing some nest materials, but where one had a few white feathers and the other had none. All three species of cavity-nesting birds studied, the pied flycatcher Ficedula hypoleuca , the blue tit Cyanistes caeruleus , and the tree swallow Tachycineta bicolor , hesitated to enter boxes with white feathers. A similar avoidance of white feathers was found when the alternative nest-box of a dyad held black feathers. However, the birds readily collected white feathers that we placed in front of their nest-box, showing the fear of such feathers was context-dependent. We suggest that naive prospecting birds may perceive feathers in nests as the result of a predation event, and that owners decorate nests with bright feathers that can be seen from the opening to deter others from entering.


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