Dynamic habitat selection by two wading bird species with divergent foraging strategies in a seasonally fluctuating wetland

Abstract For most bird species, little is known about their ecology and survival between fledging and independence despite the potential for post-fledging survival to be a factor limiting population dynamics. Cerulean Warblers (Setophaga cerulea) are a declining migratory species, and full-life-cycle conservation efforts that include the post-fledging period are warranted to attempt to reverse their decline. To understand movement, habitat selection, and survival, we radio-tracked 20 fledglings throughout the dependent post-fledging period. Broods were split by their parents, typically (88%) left parental breeding territories within 12 days, and survivors moved 2.4 ± 0.7 km (mean ± SE) from their nest within the 28.1 ± 1.8 day tracking period. Fledglings were usually observed in the mid-canopy to upper canopy and selected habitat with greater mid-story cover, less basal area, and areas closer to water bodies, compared to available points, when considering data from the entire post-fledgling period. However, habitat selection varied with fledgling age. Young fledglings (0–2 days post-fledging) selected areas with greater sapling cover and less stand basal area, but as fledglings matured, they selected areas farther from canopy gaps with greater mid-story cover. Compared with nesting habitat selected by parents, fledglings used areas with smaller and more numerous trees, fewer canopy gaps, and greater mid-story cover. Survival of the entire period was 48 ± 14% and most (8/10) mortalities occurred within the first 3 days post-fledging. Evidence indicated eastern chipmunks (Tamias striatus) as the most common predator. Providing or retaining large tracts of forest is recommended to prevent the restriction of post-fledging dispersal, and managing forests to maintain a heterogeneous landscape that includes stands with numerous canopy gaps and dense understory (e.g., shelterwood harvests or late seral stage conditions) as well as stands with a dense mid-story (e.g., younger stands and riparian areas) appears to be important for this life stage.

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Patterns of bird species richness explained by annual variation in remotely sensed Dynamic Habitat Indices

Ecological Indicators ◽

10.1016/j.ecolind.2021.107774 ◽

2021 ◽

Vol 127 ◽

pp. 107774

Author(s):

Martina L. Hobi ◽

Laura S. Farwell ◽

Maxim Dubinin ◽

Dmitrij Kolesov ◽

Anna M. Pidgeon ◽

...

Keyword(s):

Species Richness ◽

Annual Variation ◽

Bird Species ◽

Remotely Sensed ◽

Bird Species Richness ◽

Dynamic Habitat

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Inference from habitat-selection analysis depends on foraging strategies

Journal of Animal Ecology ◽

10.1111/j.1365-2656.2010.01737.x ◽

2010 ◽

Vol 79 (6) ◽

pp. 1157-1163 ◽

Cited By ~ 22

Author(s):

Guillaume Bastille-Rousseau ◽

Daniel Fortin ◽

Christian Dussault

Keyword(s):

Habitat Selection ◽

Foraging Strategies ◽

Selection Analysis

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Habitat Selection by the European Nightjar Caprimulgus europaeus in North-Eastern Poland: Implications for Forest Management

Forests ◽

10.3390/f11030291 ◽

2020 ◽

Vol 11 (3) ◽

pp. 291

Author(s):

Michał Polakowski ◽

Monika Broniszewska ◽

Lucyna Kirczuk ◽

Zbigniew Kasprzykowski

Keyword(s):

Forest Management ◽

Habitat Selection ◽

Management Practices ◽

Bird Species ◽

Environmental Parameters ◽

Timber Harvesting ◽

Forest Edge ◽

Negative Effect ◽

Caprimulgus Europaeus ◽

Management Recommendations

Research Highlights: Intensive forest management practices generally have a negative effect on biodiversity. However, the creation of new, open habitats as a consequence of timber harvesting within large areas of woodland may be favorable to some bird species. Background and Objectives: Habitat selection of the European Nightjar Caprimulgus europaeus in a coniferous woodland area in northeastern Poland was studied in order to specify management recommendations. Materials and Methods: To define the influence of various environmental parameters on territory occupation, 11 micro- and 3 macrohabitat factors were analyzed. Results: Denser vegetation in the ground layer deterred birds from nesting in clearings with such characteristics. Moreover, Nightjars preferentially inhabited sites adjacent to young stands of trees. Birds preferred plots with a higher number of clearings in the neighborhood, as this enabled them to enlarge their foraging area. Other microhabitat factors (e.g., the type, age and area of clearings), as well as macroscale factors like distances to the forest edge, nearest roads and human settlements, were of no importance. Conclusions: Knowledge of the Nightjar preferences may be useful in working out a compromise between an appropriate level of clear-felling and conservation of other bird species requiring preservation of old tree stands.

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Flock formation and the role of plumage colouration in Ardeidae

Canadian Journal of Zoology ◽

10.1139/z05-058 ◽

2005 ◽

Vol 83 (5) ◽

pp. 683-693 ◽

Cited By ~ 16

Author(s):

M Clay Green ◽

Paul L Leberg

Keyword(s):

Bird Species ◽

Flock Size ◽

Wading Birds ◽

Plumage Colouration ◽

Wading Bird ◽

White Plumage ◽

Fourth Experiment ◽

Species Specific ◽

Colour Morphs ◽

Egretta Rufescens

It has been hypothesized that white plumage facilitates flock formation in Ardeidae. We conducted four experiments using decoys to test factors involved in attracting wading birds to a specific pond. The first three experiments tested the effects of plumage colouration, flock size, and species-specific decoys on flock formation. The fourth experiment examined intraspecific differences in flock choice between the two colour morphs of the reddish egret, Egretta rufescens (Gmelin, 1789). Wading birds landed at flocks of decoys more often than single or no decoys (P < 0.001) but exhibited no overall attraction to white plumage (P > 0.05). White-plumaged species were attracted to white decoys (P < 0.001) and dark-plumaged species were attracted to dark decoys (P < 0.001). Snowy egrets (E. thula (Molina, 1782)), great egrets (Ardea alba L., 1758), and little blue herons (E. caerulea (L., 1758)) landed more often at ponds that contained decoys resembling conspecifics. At the intraspecific level, all observed reddish egrets selected flocks with like-plumaged decoys. Our results suggest that plumage colouration is an attractant for species with similar plumage, but white plumage is not an attractant for all wading bird species. White plumage may facilitate flock formation in certain species but does not serve as a universal attractant for wading birds of varying plumage colouration and size.

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Feeding associations between capybaras Hydrochoerus hydrochaeris (Linnaeus) (Mammalia, Hydrochaeridae) and birds in the Lami Biological Reserve, Porto Alegre, Rio Grande do Sul, Brazil

Revista Brasileira de Zoologia ◽

10.1590/s0101-81752005000300031 ◽

2005 ◽

Vol 22 (3) ◽

pp. 712-716 ◽

Cited By ~ 12

Author(s):

Ana C. Tomazzoni ◽

Ezequiel Pedó ◽

Sandra M. Hartz

Keyword(s):

Vegetation Type ◽

Bird Species ◽

Foraging Strategy ◽

Foraging Strategies ◽

Species Number ◽

Molothrus Bonariensis ◽

Hydrochoerus Hydrochaeris ◽

Wet Grasslands ◽

Number Of Individuals ◽

Biological Reserve

Feeding associations between capybaras Hydrochoerus hydrochaeris (Linnaeus, 1766) and some bird species were registered in the Lami Biological Reserve, southern Brazil, through observations in a set of transects established in the five major vegetation types of the study area: shrubby and herbaceous swamps, wet grasslands, sandy grasslands and forests. Data included: date and time, vegetation type, bird species, number of individuals (birds and capybaras), type of prey consumed, foraging strategy of the birds and the behavior of the capybaras in relation to the presence of birds. Five species of birds were registered: Caracara plancus (Miller, 1777), Furnarius rufus (Gmelin, 1788), Machetornis rixosus (Vieillot, 1819), Milvago chimachima (Vieillot, 1816) and Molothrus bonariensis (Gmelin, 1789). The interactions were observed in the shrubby swamp (M. bonariensis), forest (C. plancus) and wet grassland (F. rufus, M. rixosus, M. chimachima). The foraging strategies were: (1) use of the capybara as a perch, hunting from its back (M. rixosus, M. bonariensis); (2) use of the capybara as a beater, hunting in the ground (F. rufus, M. rixosus, M. bonariensis); (3) foraging in the skin of the capybara, by picking the ectoparasites (C. plancus, F. rufus, M. chimachima). Strategies (1) and (2) were employed to catch arthropods flushed from the vegetation. Sometimes, capybaras lay down and exposed the abdomen and lateral areas of their bodies to facilitate cleaning by M. chimachima, but the presence of other bird species seemed to be neutral to capybaras.

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Group structure in wood bison: nutritional and reproductive determinants

Canadian Journal of Zoology ◽

10.1139/z93-188 ◽

1993 ◽

Vol 71 (7) ◽

pp. 1367-1371 ◽

Cited By ~ 27

Author(s):

Petr E. Komers ◽

François Messier ◽

Cormack C. Gates

Keyword(s):

Habitat Selection ◽

Group Structure ◽

Dilution Effect ◽

Foraging Strategies ◽

Female Ratio ◽

Male And Female ◽

Wood Bison ◽

Males And Females ◽

Mixed Groups ◽

Male To Female

Sexual segregation in ungulates has been documented for many species including bison. However, male and female bison do not differ in their pattern of habitat selection. In the present study we observed that a fraction of bison groups did not have young (<2 years) despite the presence of males and females. The male to female ratio in these groups was 2.4. We call them adult groups, in contrast to mixed groups, where young were present and the male to female ratio was 0.4. The proportion of cows with young (mothers) in a group was negatively correlated with the male to female ratio, suggesting that mothers associated more often with other cows than with bulls. Before the rut, cows without young (non-mothers) spent less time feeding than either mothers or bulls. However, mothers and non-mothers did not differ in the number of steps per minute they took while grazing, and both types of cows stepped faster than bulls. We suggest that cows feed more selectively than bulls and that the differing foraging strategies result in temporal but not spatial segregation of the sexes. Possibly as a result of similar nutritional demands, mothers tended to aggregate, forming nursery groups. We suggest that the formation of nursery groups can also serve to protect calves through a dilution effect of predation. Whether mothers actually prefer to associate with other mothers remains to be investigated.

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Westland petrel (Procellaria westlandica) foraging behaviour: Patterns and drivers of individual variation

10.26686/wgtn.17204045.v1 ◽

2021 ◽

Author(s):

◽

Douglas Rands

Keyword(s):

Habitat Selection ◽

West Coast ◽

Foraging Behaviour ◽

Sea Surface ◽

Foraging Strategies ◽

Sea Surface Temperatures ◽

The West ◽

Surface Temperatures ◽

Foraging Site ◽

Incidental Mortality

Foraging behaviour can have a major influence on the survival and reproduction of individuals which can ultimately impact the viability of a population. Foraging is particularly challenging for procellariiformes (tube nosed seabirds) who feed on patchily distributed prey in the highly dynamic marine environment. During the breeding season procellariiformes must also increase their foraging effort to raise their chick whilst having a reduced foraging range. As a result, procellariiformes have adopted various foraging strategies, such as dual foraging and sexual foraging dimorphism, to cope with this energy demanding lifestyle. Westland petrels (Procellaria westlandica) are an endangered winter breeding procellariform endemic to the West Coast of New Zealand’s South Island. Unlike other procellariiformes, previous studies have found little evidence of Westland petrels using sexually dimorphic or dual foraging strategies. Furthermore, Westland petrels also display a high level of individual variation in foraging behaviour. To understand why there is so much variation and what factors are driving it, I first examined variation at the population, individual and within individual level to describe and categorise different foraging strategies. I then investigated how factors such as year, sex and foraging site influenced variation. Finally, I examined how oceanic variables influenced habitat selection and foraging characteristics to understand how the environment drives variation in foraging behaviour. Considerable variation was found at all levels. Most of the variation was explained by year with individuals taking shorter foraging trips in 2011 and longer trips in 2015. Females foraged further than males suggesting that there is some degree of sexual foraging segregation occurring in Westland petrels. I also found that the highest variation in foraging behaviour was exhibited by individuals within their core foraging site on the West Coast. Sea surface temperatures were highest at the West Coast foraging site and individuals within this site showed differences in habitat selection among years. Habitat selection at the West Coast site also differed between sexes suggesting that males are outcompeting females for prime foraging spots. Overall, my results indicate that foraging conditions on the West Coast are highly variable likely due to rising sea surface temperatures, marine heatwaves, and the effects of the El Nino-Southern Oscillation. As a result, it is likely that prey availability on the West Coast is unpredictable causing high variation in foraging behaviour and sexual foraging segregation. With climate change, foraging conditions on the West Coast are predicted to get more unpredictable as sea surface temperatures continue to rise and extreme weather events become more frequent. These factors will make foraging increasingly difficult for Westland petrels and could see them rely more on fishery discards as a source of food, increasing their risk of incidental mortality. Conservation management should focus on protecting the petrels core foraging area around the Hokitika canyon to help limit the effects of climate change. Fishery management should also focus on limiting or prohibiting offal discards to prevent the incidental mortality of Westland petrels.

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Westland petrel (Procellaria westlandica) foraging behaviour: Patterns and drivers of individual variation

10.26686/wgtn.17204045 ◽

2021 ◽

Author(s):

◽

Douglas Rands

Keyword(s):

Habitat Selection ◽

West Coast ◽

Foraging Behaviour ◽

Sea Surface ◽

Foraging Strategies ◽

Sea Surface Temperatures ◽

The West ◽

Surface Temperatures ◽

Foraging Site ◽

Incidental Mortality

Foraging behaviour can have a major influence on the survival and reproduction of individuals which can ultimately impact the viability of a population. Foraging is particularly challenging for procellariiformes (tube nosed seabirds) who feed on patchily distributed prey in the highly dynamic marine environment. During the breeding season procellariiformes must also increase their foraging effort to raise their chick whilst having a reduced foraging range. As a result, procellariiformes have adopted various foraging strategies, such as dual foraging and sexual foraging dimorphism, to cope with this energy demanding lifestyle. Westland petrels (Procellaria westlandica) are an endangered winter breeding procellariform endemic to the West Coast of New Zealand’s South Island. Unlike other procellariiformes, previous studies have found little evidence of Westland petrels using sexually dimorphic or dual foraging strategies. Furthermore, Westland petrels also display a high level of individual variation in foraging behaviour. To understand why there is so much variation and what factors are driving it, I first examined variation at the population, individual and within individual level to describe and categorise different foraging strategies. I then investigated how factors such as year, sex and foraging site influenced variation. Finally, I examined how oceanic variables influenced habitat selection and foraging characteristics to understand how the environment drives variation in foraging behaviour. Considerable variation was found at all levels. Most of the variation was explained by year with individuals taking shorter foraging trips in 2011 and longer trips in 2015. Females foraged further than males suggesting that there is some degree of sexual foraging segregation occurring in Westland petrels. I also found that the highest variation in foraging behaviour was exhibited by individuals within their core foraging site on the West Coast. Sea surface temperatures were highest at the West Coast foraging site and individuals within this site showed differences in habitat selection among years. Habitat selection at the West Coast site also differed between sexes suggesting that males are outcompeting females for prime foraging spots. Overall, my results indicate that foraging conditions on the West Coast are highly variable likely due to rising sea surface temperatures, marine heatwaves, and the effects of the El Nino-Southern Oscillation. As a result, it is likely that prey availability on the West Coast is unpredictable causing high variation in foraging behaviour and sexual foraging segregation. With climate change, foraging conditions on the West Coast are predicted to get more unpredictable as sea surface temperatures continue to rise and extreme weather events become more frequent. These factors will make foraging increasingly difficult for Westland petrels and could see them rely more on fishery discards as a source of food, increasing their risk of incidental mortality. Conservation management should focus on protecting the petrels core foraging area around the Hokitika canyon to help limit the effects of climate change. Fishery management should also focus on limiting or prohibiting offal discards to prevent the incidental mortality of Westland petrels.

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