scholarly journals Winter Flocking of Insectivorous Birds in Montane Pine-Oak Forests in Middle America

The Condor ◽  
2000 ◽  
Vol 102 (3) ◽  
pp. 664-672 ◽  
Author(s):  
David I. King ◽  
John H. Rappole
Keyword(s):  
Foraging Behavior ◽  
Bird Species ◽  
Oak Forests ◽  
Mixed Species ◽  
Predator Detection ◽  
Species Pairs ◽  
Middle America ◽  
Vegetation Characteristics ◽  
Mixed Species Flocks ◽  
Positive Correlations

Abstract We studied mixed-species insectivorous bird flocks in pine-oak forests in Middle America during three winter seasons to determine whether patterns of flock structure and dynamics were similar to those reported from other tropical sites. We also analyzed patterns of association among bird species, as well as their foraging behavior and the vegetation characteristics associated with birds in flocks. We encountered 333 flocks containing 144 species, of which 26 species had adequate sample sizes for analyses. The size and rate of movement of the flocks were similar to those reported from other Neotropical sites, however, the species richness of our flocks was lower than reported in most other studies, perhaps due to simpler vegetation structure or higher latitude. Only 3 of 50 significant correlations between species pairs were negative, indicating that species generally were not restricted in their participation in mixed-species flocks by other species. In only one instance did we observe correspondence between the association of species-pairs in flocks and their foraging behavior. For most species there was no relationship between association between species-pairs in flocks and vegetation parameters with which they were associated. Thus, additional factors besides foraging facilitation and mutual association with particular vegetation characteristics must be responsible for many of the positive correlations among species pairs. We suggest that non-random association among species within flocks may result in part from enhanced vigilance for predator detection afforded by flock members using similar parts of the environment at the same time.

Social learning and the significance of mixed-species flocks of chickadees (Parus spp.)

1973 ◽  
Vol 51 (12) ◽  
pp. 1275-1288 ◽  
Author(s):  
John R. Krebs
Keyword(s):  
Social Learning ◽  
Foraging Behavior ◽  
Food Item ◽  
Adaptive Significance ◽  
The Other ◽  
Mixed Species ◽  
The Third ◽  
Mixed Species Flocks ◽  
Species Flocks ◽  
Experienced Bird

The experiments described in this paper show that two species of chickadees learn from one another about the location and nature of potential feeding places when they are foraging together in mixed flocks in large aviaries. In the first experiment, I show that when an individual of one species finds a single food item, members of the other species modify their foraging behavior over the next few seconds so that they put more effort into searching near the site of the find. This applies to both species. Further, members of both species modify their foraging behavior when a bird of the other species searches in a place unsuccessfully. This response to an unsuccessful search is similar to, but weaker than, the response to a food find. The second experiment shows that when the two species are trained to forage in different positions in the experimental trees, they converge in their foraging behavior when they are put in mixed flocks, This is a result of copying. The third experiment shows that individuals of both species are more likely to discover a completely new foraging place if they are in the presence of an experienced bird of the other species.I discuss these results in relation to theories on the adaptive significance of flocking, and conclude that learning about potential feeding places from other species is an important function of mixed flocks, at least for some species. This does not exclude the possibility of other functions of mixed flocks.

Are disturbance separation distances derived from single species applicable to mixed-species shorebird flocks?

2019 ◽  
Vol 46 (8) ◽  
pp. 719 ◽  
Author(s):  
Grant D. Linley ◽  
Patrick-Jean Guay ◽  
Michael A. Weston
Keyword(s):  
Bird Species ◽  
Single Species ◽  
Scientific Basis ◽  
Mixed Species ◽  
Constituent Species ◽  
Scant Attention ◽  
Species Groups ◽  
Mixed Species Flocks ◽  
System Separation ◽  
Species Flocks

Abstract ContextHuman disturbance threatens many bird species worldwide. Flight-initiation distances (FIDs) offer a scientific basis for separation distances between fauna and agents of disturbance, such as people. However, most available FIDs are from single-species groups. Multi-species flocks have received scant attention with regard to their FIDs; yet, they are extremely common in nature. AimTo examine suitable separation distances for mixed-species shorebird flocks by comparing single-species FIDs with those of the same species in mixed-species flocks. MethodWe examined FIDs in mixed- and single-species flocks of four shorebirds (double-banded plover, Charadrius bicinctus, red-capped plover, Charadrius ruficapillus, red-necked stint, Calidris ruficollis, and curlew sandpiper, Calidris ferruginea). FIDs were collected in comparable habitat and sites with similar (i.e. highly restricted) regimes of human occurrence. ResultsFIDs of single-species flocks of these species differed in their FID to an approaching walker. Different species permutations in mixed-species flocks resulted in different FIDs. FIDs of mixed-species flocks were lower than or the same as the FIDs of single-species groups of constituent species. Conclusions and implicationsIn our study system, separation distances (e.g. buffers; zones that exclude humans to reduce shorebird disturbance) based on FIDs of single species also would be efficacious for mixed-species flocks containing those species.

scholarly journals Phenotypic Clumping Decreases With Flock Richness in Mixed-Species Bird Flocks

2021 ◽  
Vol 8 ◽  
Author(s):  
Priti Bangal ◽  
Hari Sridhar ◽  
Kartik Shanker
Keyword(s):  
Body Size ◽  
Foraging Behavior ◽  
Group Size ◽  
Positive Interactions ◽  
Flock Size ◽  
Mixed Species ◽  
Taxonomic Relatedness ◽  
Western Ghats Of India ◽  
Mixed Species Flocks ◽  
Species Flocks

Animals that live in groups may experience positive interactions such as cooperative behavior or negative interactions such as competition from group members depending on group size and similarity between individuals. The effect of group size and phenotypic and ecological similarity on group assembly has not been well-studied. Mixed-species flocks are important subsets of bird communities worldwide. We examined associations within these in relation to flock size, to understand rules of flock assembly, in the Western Ghats of India. We examined the relationship between phenotypic clumping and flock richness using four variables—body size, foraging behavior, foraging height and taxonomic relatedness. Using a null model approach, we found that small flocks were more phenotypically clumped for body size than expected by chance; however, phenotypic clumping decreased as flocks increased in size and approached expected phenotypic variation in large flocks. This pattern was not as clear for foraging height and foraging behavior. We then examined a dataset of 55 flock matrices from 24 sites across the world. We found that sites with smaller flocks had higher values of phenotypic clumping for body size and sites with larger flocks were less phenotypically clumped. This relationship was weakly negative for foraging behavior and not statistically significant for taxonomic relatedness. Unlike most single-species groups, participants in mixed-species flocks appear to be able to separate on different axes of trait similarity. They can gain benefits from similarity on one axis while mitigating competition by dissimilarity on others. Consistent with our results, we speculate that flock assembly was deterministic up to a certain point with participants being similar in body size, but larger flocks tended to approach random phenotypic assemblages of species.

scholarly journals Do similar foragers flock together? Nonbreeding foraging behavior and its impact on mixed-species flocking associations in a subtropical region

The Auk ◽  
2020 ◽  
Vol 137 (2) ◽  
Author(s):  
Harrison H Jones ◽  
Mitchell J Walters ◽  
Scott K Robinson
Keyword(s):  
Foraging Behavior ◽  
Relative Abundance ◽  
Foraging Ecology ◽  
Fine Scale ◽  
Mixed Species ◽  
Substrate Use ◽  
Nonbreeding Season ◽  
Abundance Patterns ◽  
Mixed Species Flocks ◽  
Species Flocks

Abstract Mixed-species flocks are ubiquitous in forest bird communities, yet the extent to which positive (facilitative) or negative (competitive) interactions structure these assemblages has been a subject of debate. Here, we describe the fine-scale foraging ecology and use network analysis to quantify mixed-species flocking interactions of an insectivorous bird community in hardwood forests of north-central Florida. Our goal was to determine if similarly foraging species are more (facilitation hypothesis) or less (competition hypothesis) likely to associate in flocks, and if foraging ecology can explain intraspecific abundance patterns within flocks. We quantified attack maneuvers, foraging substrate, and foraging microhabitat of all 17 common insectivorous species in these forests and characterized the composition of 92 flocks encountered. Flocking was important in our community; 14 of 17 species joined more than 5% of flocks, and 10 species had flocking propensities of over 0.80. Our results supported both hypothesized mechanisms structuring flock composition. Species had distinct, well-defined foraging niches during the nonbreeding season, but foraging niche overlap among flocking species was greater than expected by chance. Consistent with the facilitation hypothesis, we found that similarly foraging species were significantly more likely to associate in flocks, a result driven by lower association strengths in large-bodied woodpeckers. We found no evidence of assortment by foraging behavior, however, likely because foraging behavior and substrate use showed strong niche partitioning at the fine scale within our community. Intraspecific abundance patterns were significantly linked to foraging substrate use, with live leaf use correlated with high within-flock abundance and relative abundance at study sites. Species that specialized on comparatively less abundant substrates (tree trunks, epiphytes, dead leaves) joined flocks as singletons, showed lower relative abundance, and may exhibit nonbreeding territoriality. Our results highlight the importance of foraging substrate use and mixed-species flocks in structuring the nonbreeding ecology of migratory birds.

scholarly journals Evaluating the role of contracting and expanding rainforest in initiating cycles of speciation across the Isthmus of Panama

2012 ◽  
Vol 279 (1742) ◽  
pp. 3520-3526 ◽  
Author(s):  
Brian Tilston Smith ◽  
Amei Amei ◽  
John Klicka
Keyword(s):  
Bird Species ◽  
Tropical Regions ◽  
Isthmus Of Panama ◽  
Species Pairs ◽  
The Matrix ◽  
High Species Richness ◽  
The Rich ◽  
The Tropics ◽  
The Impact

Climatic and geological changes across time are presumed to have shaped the rich biodiversity of tropical regions. However, the impact climatic drying and subsequent tropical rainforest contraction had on speciation has been controversial because of inconsistent palaeoecological and genetic data. Despite the strong interest in examining the role of climatic change on speciation in the Neotropics there has been few comparative studies, particularly, those that include non-rainforest taxa. We used bird species that inhabit humid or dry habitats that dispersed across the Panamanian Isthmus to characterize temporal and spatial patterns of speciation across this barrier. Here, we show that these two assemblages of birds exhibit temporally different speciation time patterns that supports multiple cycles of speciation. Evidence for these cycles is further corroborated by the finding that both assemblages consist of ‘young’ and ‘old’ species, despite dry habitat species pairs being geographically more distant than pairs of humid habitat species. The matrix of humid and dry habitats in the tropics not only allows for the maintenance of high species richness, but additionally this study suggests that these environments may have promoted speciation. We conclude that differentially expanding and contracting distributions of dry and humid habitats was probably an important contributor to speciation in the tropics.

Using playback to test leadership in mixed-species flocks and compare flocking with mobbing

2021 ◽  
Vol 180 ◽  
pp. 151-166
Author(s):  
Liping Zhou ◽  
Indika Peabotuwage ◽  
Kang Luo ◽  
Rui-Chang Quan ◽  
Eben Goodale
Keyword(s):  
Mixed Species ◽  
Mixed Species Flocks ◽  
Species Flocks

Why Do Brown-Headed Cowbirds Perform the Head-Down Display?

The Auk ◽  
1983 ◽  
Vol 100 (1) ◽  
pp. 139-148 ◽  
Author(s):  
Thomas W. Scott ◽  
Judith M. Grumstrup-Scott
Keyword(s):  
Observational Data ◽  
Agonistic Behavior ◽  
Mixed Species ◽  
House Sparrows ◽  
Mixed Species Flocks ◽  
Free Ranging ◽  
Species Flocks

Abstract Four hypotheses for the function of the head-down display performed by Brown-headed Cowbirds were tested with observational data from free-ranging and captive cowbirds. Free-ranging cowbirds performed 284 interspecific and four intraspecific displays during 59.2 daylight hours while roosting in mixed-species flocks adjacent to feeding areas. The most common recipients of displays, female Red-winged Blackbirds and House Sparrows, preened cowbirds during 25 displays. Cowbirds that had just been preened displayed more often than those that had not recently been preened. Captive cowbirds displayed intraspecifically 475 times during 13.3 h, and dominant captive birds displayed more often than their subordinates. The following hypothesis was proposed to explain the display's function: the head-down display of Brown-headed Cowbirds is an appeasing agonistic behavior, the displayor is most often dominant to the recipient, and subsequent displaying is stimulated by interspecific preening. The display may function in: (a) obtaining food, (b) minimizing roosting energetics, and/or (c) establishing flock order.

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