Effects of feeding height and distance from protective cover on the foraging behavior of wintering birds

2005 ◽  
Vol 83 (6) ◽  
pp. 880-890 ◽  
Author(s):  
Ya-Fu Lee ◽  
Yen-Min Kuo ◽  
Eric K Bollinger
Keyword(s):  
Foraging Behavior ◽  
Risk Avoidance ◽  
Mixed Species ◽  
Feeding Efficiency ◽  
Parus Carolinensis ◽  
Parus Bicolor ◽  
Protective Cover ◽  
Number Of Visits ◽  
Set Up ◽  
Open Fields

Foraging behavior that balances feeding efficiency with predation risk avoidance may be selected for; thus, foraging animals may choose among sites and achieve various giving-up densities under different feeding conditions. We compared the frequency and duration of visits and the feeding efficiency of a mixed-species wintering bird flock among feeders set up at three heights within woods, at the edge between woods and dense shrub, and in open fields to investigate the feeding height preference of birds and its relationship to the extent of openness of the sites. Carolina chickadees (Parus carolinensis Audubon, 1834) and tufted titmice (Parus bicolor L., 1766) accounted for 96% of the total number of visits to feeders and 95.9% of the total time spent on feeders. Birds tended to visit higher feeders and feeders in the woods and at edge sites more frequently than they visited lower feeders and feeders in open fields. Birds also spent more time on higher feeders and feeders in the woods and at edge sites than on lower feeders and feeders in open fields. However, the feeding height preference changed over the course of observations, and different patterns were observed at different sites. In the woods and at the edge, bird visits shifted to the lower feeders earlier; in contrast, birds preferred higher feeders throughout the period of observation in open fields. Feeding efficiency was lower at open sites than in woods and at edge sites, but birds spent the least time per seed on low feeders at open sites. Seeds on higher feeders and in woods or at edge sites were removed faster. Regardless of the height and locality of feeders, birds preferred energy-rich oil-type seeds over energy-poor striped seeds.

scholarly journals Effects of Body Size and Sex on Foraging Territoriality of the Little Egret (Egretta Garzetta) in Japan

The Auk ◽  
2003 ◽  
Vol 120 (3) ◽  
pp. 791-798 ◽  
Author(s):  
Yukiko Nota
Keyword(s):  
Body Size ◽  
Foraging Behavior ◽  
Foraging Efficiency ◽  
Type I ◽  
Long Period ◽  
Foraging Area ◽  
Feeding Efficiency ◽  
Strong Attachment ◽  
Little Egret ◽  
Egretta Garzetta

Abstract I studied the characteristics of foraging territoriality in the Little Egret (Egretta garzetta) and effects of body size and sex on territoriality. Sixty-eight birds were captured and sexed, and foraging behavior (usage of area, defense rate, and foraging efficiency) of 26 birds identified by color bands was observed in detail for 3 years. I categorized territoriality within the foraging area into three types according to the birds' exclusiveness and attachment to the area: high exclusiveness and strong attachment to the same area for a long period, moderate exclusiveness and attachment, and minimal exclusiveness and attachment. Body size was largest and feeding efficiency was highest in the first type. I propose a model that predicts a relationship between body size and defense rate to explain the behavior of egrets.

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.

Mixed-Species Flocking and Foraging Behavior of Four Neotropical Warblers in Panamanian Shade Coffee Fields and Forests

The Auk ◽  
2003 ◽  
Vol 120 (4) ◽  
pp. 1000-1012 ◽  
Author(s):  
Lars Y. Pomara ◽  
Robert J. Cooper ◽  
Lisa J. Petit
Keyword(s):  
Foraging Behavior ◽  
Mixed Species ◽  
Shade Coffee

Time Budgets, Feeding Efficiency and Flock Dynamics in Mixed Species Flocks of Lapwings, Golden Plovers and Gulls

Behaviour ◽  
1982 ◽  
Vol 80 (1-2) ◽  
pp. 44-69 ◽  
Author(s):  
D.B.A. Thompson ◽  
C.J. Barnard ◽  
Hilary Stephens
Keyword(s):  
Energy Intake ◽  
Time Budget ◽  
Mixed Species ◽  
Feeding Efficiency ◽  
Large Numbers ◽  
Directional Change ◽  
Negative Effect ◽  
Flock Dynamics ◽  
Mixed Species Flocks ◽  
Species Flocks

Abstract1. In mixed species flocks of lapwings and golden plovers, lapwing net rate of energy intake was positively related to the number of conspecifics and the amount of time individuals spent crouching during feeding, but was unaffected by the presence of golden plovers. Plover net rate of energy intake, however, was positively related to crouching tendency, negatively related to the number of lapwings present but unaffected by the number of conspecifics. 2. Golden plovers appeared to join lapwing flocks because they could then crouch more and scan less. The independent negative effect of lapwing number may have been due to feeding interference when there were large numbers of lapwings relative to plovers. 3. When black-headed gulls joined a flock, both lapwings and plovers tended to crouch less and take smaller worms. However, in lapwings these changes appeared to reduce feeding efficiency but plover net rate of energy intake increased as a function of the gull: plover ratio. 4. When gulls were present, the effect of conspecifics on lapwing feeding efficiency disappeared and the presence of plovers had a negative effect. Conversely, in plovers the presence of conspecifics enhanced feeding efficiency and the negative effect of lapwing number disappeared. 5. The arrival of gulls resulted in a decrease in equilibrium lapwing number but no consistent, directional change in plover number. When gulls were present, lapwing number tended to decrease when large numbers of plovers arrived, but increase when small numbers arrived. Increased lapwing number had no significant directional effect on plover number. Changes in lapwing and plover energy intake and species numbers are interpreted in terms of feeding interference and 'dilution' of gull kleptoparasitism. 6. In the absence of gulls, there was no significant directional relationship between increased plover number and lapwing number, but the presence of plovers generally correlated with a reduction in lapwing number. Plover number, however, decreased when large numbers of additional lapwings arrived but increased with small numbers of arrivals. Changes in species energy intake and numbers here are interpreted in terms of feeding interference and time budget changes.

scholarly journals Short-Term Responses to Salinity of Soybean and Chenopodium album Grown in Single and Mixed-Species Hydroponic Systems

Agronomy ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1481
Author(s):  
Aurora Ghirardelli ◽  
Michela Schiavon ◽  
Giuseppe Zanin ◽  
Piotr Ostapczuk ◽  
Roberta Masin
Keyword(s):  
Salt Stress ◽  
Protein Content ◽  
Crop Yields ◽  
Chenopodium Album ◽  
Mixed Species ◽  
Dramatic Decline ◽  
Glycine Max L ◽  
K Concentration ◽  
Set Up ◽  
Condition C

Weeds account for losses in crop yields, and this event might be exacerbated by salinity. Therefore, we investigated the responses of Chenopodium album L. and soybean (Glycine max (L.) Merr.) to salt stress, as well as interferences between species. Ten-day old plants were grown for 1 week in a single- or mixed-species set-up, either with or without 100 mM of NaCl. C. album reduced the biomass of soybean similarly to salt stress, while its growth was unaffected under any condition. C. album decreased the crop protein content when salinity was applied. This effect was ascribed to altered protein metabolism and/or N usage to produce other N metabolites, including osmolytes. The two species did not reciprocally affect the capacity to accumulate Na+, but the weed contained two-fold more Na+ in the leaves. Elevated initial K+ concentration and high K+ delivery to the shoot likely explained the better acclimation of C. album to salinity. C. album produced more phenolics and proline and exhibited greater antioxidant activity, but low lipid peroxidation, in the mixed set-up under salinity. Thus, it is possible that the weed could become more resilient to salinity when growing in a soybean field. In the long term, this might cause significant losses in soybean productivity as expected by the dramatic decline in crop protein content.

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 Assessing a risk-avoidance navigation system based on localized torrential rain data

2020 ◽  
Vol 308 ◽  
pp. 03006
Author(s):  
Sadanori Ito ◽  
Zettsu Koji
Keyword(s):  
Early Detection ◽  
Driving Simulator ◽  
Heavy Rain ◽  
Guidance System ◽  
Route Guidance ◽  
Risk Avoidance ◽  
Torrential Rain ◽  
Four Levels ◽  
Set Up ◽  
Traffic Optimization

Localized torrential rainfall events and related traffic problems are increasing in Japan, suggesting the need for a navigation-alert system to help drivers avoid such risks. Based on ongoing developments of weather radar systems for early detection of localized torrential rain and a cross-data collaboration platform for traffic optimization, in this study we tested the application of a route-guidance system that can help drivers avoid heavy rainfall. Participants were given equivalent levels of pre-training un the early detection of rainfall and the relationship between rainfall and accidents, then allowed to test a driving simulator set up with four alert methods, three route options, and four levels of possible risk avoidance. Using this system, the heavy rain avoidance rate was 85.63%, suggesting that such a system would be socially acceptable and useful, though further research is needed to refine the specific approach.

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