DOCSLIB.ORG

A Classification Scheme for Foraging Behavior of Birds in Terrestrial Habitats

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text

Load more

Studies in Avian Biology No. 13:144-160, 1990. A CLASSIFICATION SCHEME FOR FORAGING BEHAVIOR OF BIRDS IN TERRESTRIAL HABITATS J.V. REMSEN,JR. AND SCOTT KROBINSON Abstract. Studiesofavian foragingbehavior in terrestrialhabitats sufferfrom a lack of standardization in the kinds of data gathered and in the terminology used to classify different activities. These incon- sistenciespartially reflect the variety of questionsasked about foraging.If a standardterminology were used, then data on foraging behavior could be included among the standard data (e.g., clutch size, body weight, and mating system) routinely recorded for the biology of a bird species. We propose a system for gathering foraging data for landbirds in which the five basic, sequential componentsofforaging (search,attack, foragingsite, food, and food handling) are quantified separately. Data on searchingbehavior involve measuring continuous variables and are particularly critical for studies of energetics. The “attack” component is most in need of standardized terminology. The system that we propose separatesthe attack perch from the attack maneuver, and further subdivides the maneuvers into near-perch, subsurface,and aerial maneuvers. Each of these general categoriesis further subdivided according to details of attack movements and ways in which substratesare ma- nipulated. Data on attack methods are primarily useful for studies of ecomorphology, but may also be important in bioenergeticand community-level studies. Quantifying the foraging site involves measuring the following variables: general habitat (location in a study area), vertical position, foliage density, and substrate.Although identification and quanti- fication of foods taken in the field is difficult, it can provide valuable information on food size (and taxon for largeritems). Dietary data from stomachsamples are usefulfor studiesof resourcepartitioning when they show dramatic differences,but overlapping diets do not necessarilyindicate that two birds forage in the same way. Food-handling behavior is seldom measured in the field, but is valuable in studiesof optimal foraging behavior and ecomorphology. Intercorrelations between each of these aspectsof foraging can be determined from standard multi- variate analyses.How finely to subdivide categoriesdepends upon the kinds of questionsbeing asked. Key Words: Foraging behavior classification;foraging maneuvers; search;attack; foraging site; diet; food-handling; glean; sally; probe; manipulate. There are almost as many ways of classifying quantify foraging. For example, the “hawk” cat- and quantifying foraging behavior as there are egory of Sherry (1979) and Holmes et al. (1978, papers on the subject. In part, this variety reflects 1979b) includes attacks on prey animals that were the fact that no two species or groups of species flying when first seen, attacks on prey flushed forage in exactly the same way, and that no two from foliage by the foraging activities of the bird, habitats present exactly the same foraging op- and chases after prey that the bird attacked and portunities. It is difficult, for example, to quan- missed. Later papers by Robinson and Holmes tify the foraging methods of bark-foragers in the (1982, 1984) and Sherry (1983, 1984) however, same way that one quantifies the foraging of fo- showed that differences among these aerial ma- liage-foragers (Jackson 1979). Another factor neuvers have important implications for diet. contributing to the lack of standardization is that Remsen (1985) showed that the fine details of different kinds of questions often require differ- substrate use (e.g., dead leaves, moss) that are ent kinds of data. Many studies that focus on often ignored in many community studies were resource partitioning record only the details of particularly important in resource partitioning in foraging site selection and omit data on search a tropical bird community. Rosenberg (this vol- and attack movements (e.g., Hertz et al. 1976). ume) further showed that even within a group as In contrast, studies of ecomorphology emphasize specialized as dead-leaf foragers, species differ in prey-attack methods (e.g., Osterhaus 1962; Fitz- the kinds of suspended dead leaves that they patrick 1980, 1985) whereas bioenergetic and search. The classification of foraging behavior, optimal foraging studies emphasize searching therefore, is more than a semantic problem: one movements as well as prey handling (e.g., Sherry can reach different conclusions simply by clas- and McDade 1982, Robinson 1986). Even stud- sifying foraging methods differently. ies addressing the same questions in ecologically In this paper, we propose a system for mea- similar birds do not always measure the same suring and classifying foraging behavior for non- variables. raptorial landbirds. Our goal is to standardize This lack of standardization, however, reflects data-gathering methods and terminology to per- fundamental inconsistencies in the importance mit among-site and among-species comparisons attached to the individual variables used to that are currently handicapped by the absence of 144 CLASSIFICATION OF BEHAVIOR--Remsen and Robinson 145 a common vocabulary. If some standard system volume). We discuss briefly data on bird diets, and terminology were used by those studying and also propose a standard terminology for food- foraging behavior, then we could ask questions handling techniques. The final section of our pa- concerning the frequencies of various behaviors per deals with some of the ways in which data among communities. Such comparisons may can be analyzed to address questions of resource- provide important insights into community or- partitioning, bioenergetics, and ecomorphology. ganization: in a field such as foraging behavior, in which community-wide experimental manip- SEARCHING BEHAVIOR ulations are difficult or limited, a comparative Searching behavior includes those movements used approach among species and communities may to search for food or substrates that hide food; under be the only method available for testing many our definition of searching behavior, “search” ends hypotheses. once food or food-hiding substrates are sighted and The system presented here separates five se- attacked. Searching methods have usually been quan- quential components of foraging behavior, each tified by recording the lengths and rates of movements of which is quantified separately when data are between perches and the time intervals between move- gathered in the field: (1) search (movements lead- ments (e.g., MacArthur 1958, Cody 1968, Williamson ing up to sighting of food or food-concealing sub- 197 1, Fitzpatrick 198 1, Robinson and Holmes 1982). Other variables are: (1) distance covered per unit time; strates); (2) attack (movements directed at food (2) number of stops and time-spent-stopped per unit item or the substrate that conceals it once sight- time; (3) number of attacks (and % successful) per unit ed); (3) foraging site (including general location time; (4) direction ofmovement between stops, in three and specific substrate); (4) food (including type dimensions if appropriate; (5) sequential distribution and size); and (5) food handling (after food item of locations of stops (to calculate return rates to pre- obtained). We recognize that many of these com- vious stops). Between-foraging-site movements can be ponents are not necessarily independent, but we categorized as: (1) walk, (2) hop, (3) jump (leg-powered prefer to quantify each separately and to allow leaps that cover more space than the typical hop), (4) subsequent analyses to show intercorrelations. run, (5) climb (with notations on whether or not the tail is used as a brace), (6) glide, (7) flutter, and (8) fly. At the outset, we recognize that any classifi- Robinson and Holmes (1984) further distinguished be- cation system inflicts typology on what may be tween hops in which American Redstarts (Setophagu gradients of behavior, but we see no other prac- ruticilla) fanned their tails and lowered their wings, tical solution for organizing foraging informa- and hops in which there were no extra movements. tion. Our goal is to distinguish among what we Some birds also use their wings for support when hop- subjectively perceive to be functionally different ping on thin, weak perches, a movement that could be categories. By using standardized terminology, called a “flutter-hop” (Robinson, unpubl. data). Also data on foraging behavior can be included among of interest are postures during searching that are sel- the standard biological data reported for bird dom qualitatively described (for exceptions, see any E. 0. Willis reference) or quantified but that may have species. At present, reference works on birds, subtle morphological correlates. Postures are particu- which typically include detailed, quantitative data larly difficult to categorize because most species move on variables such as clutch size, body weight, and change postures frequently, and because head, wing, molt and migration schedule, and mating sys- and tail orientations are all simultaneously involved. tem, tend to omit, or describe in superficial, qual- Perhaps the advent of telephoto video-cameras will itative ways, all aspects of foraging behavior ex- permit such analyses; in this paper we deal with pos- cept perhaps diet. Foraging data should be tures only peripherally. More amenable to quantifi- included in such reference works, because for- cation are changes of orientation while searching from aging behavior is an
Recommended publications
  • Territory Size and Stability in a Sedentary Neotropical Passerine: Is Resource Partitioning a Necessary Condition?

    Territory Size and Stability in a Sedentary Neotropical Passerine: Is Resource Partitioning a Necessary Condition?

    J. Field Ornithol. 76(4):395±401, 2005 Territory size and stability in a sedentary neotropical passerine: is resource partitioning a necessary condition? Janet V. Gorrell,1 Gary Ritchison,1,3 and Eugene S. Morton2 1 Department of Biological Sciences, Eastern Kentucky University, Richmond, Kentucky 40475 USA 2 Hemlock Hill Field Station, 22318 Teepleville Flats Road, Cambridge Springs, Pennsylvania 16403 USA Received 9 April 2004; accepted 11 April 2005 ABSTRACT. Long-term pair bonds and defense of territories year-round are common among tropical passer- ines. The boundaries of these territories tend to be stable, perhaps re¯ecting the need to defend an area that, regardless of conditions, provides suf®cient food resources. If, however, these stable territories are not, even tem- porarily, suf®ciently large, then intra-pair competition for available food may result, particularly in species with no sexual size dimorphism. With such competition, sex-speci®c differences in foraging behavior may result. Male and female Dusky Antbirds (Cercomacra tyrannina) are not size dimorphic, and pairs jointly defend territories throughout the year. Our objective was to determine if paired Dusky Antbirds exhibited sex-speci®c differences in foraging behavior. Foraging antbirds were observed in central Panama from February±July 2002 to determine if pairs par- titioned food resources. Males and females exhibited no differences in foraging behavior, with individuals of both sexes foraging at similar heights and using the same foraging maneuvers (glean, probe, and sally) and substrates (leaves, rolled leaves, and woody surfaces). These results suggest that Dusky Antbirds do not partition resources and that territory switching, rather than resource partitioning, may be the means by which they gain access to additional food resources.
  • The All-Bird Bulletin

    The All-Bird Bulletin

    Advancing Integrated Bird Conservation in North America Spring 2014 Inside this issue: The All-Bird Bulletin Protecting Habitat for 4 the Buff-breasted Sandpiper in Bolivia The Neotropical Migratory Bird Conservation Conserving the “Jewels 6 Act (NMBCA): Thirteen Years of Hemispheric in the Crown” for Neotropical Migrants Bird Conservation Guy Foulks, Program Coordinator, Division of Bird Habitat Conservation, U.S. Fish and Bird Conservation in 8 Wildlife Service (USFWS) Costa Rica’s Agricultural Matrix In 2000, responding to alarming declines in many Neotropical migratory bird popu- Uruguayan Rice Fields 10 lations due to habitat loss and degradation, Congress passed the Neotropical Migra- as Wintering Habitat for tory Bird Conservation Act (NMBCA). The legislation created a unique funding Neotropical Shorebirds source to foster the cooperative conservation needed to sustain these species through all stages of their life cycles, which occur throughout the Western Hemi- Conserving Antigua’s 12 sphere. Since its first year of appropriations in 2002, the NMBCA has become in- Most Critical Bird strumental to migratory bird conservation Habitat in the Americas. Neotropical Migratory 14 Bird Conservation in the The mission of the North American Bird Heart of South America Conservation Initiative is to ensure that populations and habitats of North Ameri- Aros/Yaqui River Habi- 16 ca's birds are protected, restored, and en- tat Conservation hanced through coordinated efforts at in- ternational, national, regional, and local Strategic Conservation 18 levels, guided by sound science and effec- in the Appalachians of tive management. The NMBCA’s mission Southern Quebec is to achieve just this for over 380 Neo- tropical migratory bird species by provid- ...and more! Cerulean Warbler, a Neotropical migrant, is a ing conservation support within and be- USFWS Bird of Conservation Concern and listed as yond North America—to Latin America Vulnerable on the International Union for Conser- Coordination and editorial vation of Nature (IUCN) Red List.
  • Foraging Niche Structure and Coexistence in a Highly Diverse Community Of

    Foraging Niche Structure and Coexistence in a Highly Diverse Community Of

    Foraging niche structure and coexistence in a highly diverse community of Amazonian antbirds (Thamnophilidae: Aves) by SANTIAGO DAVID B.Sc, Universidad de Antioquia, 2011 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE in THE FACULTY OF GRADUATE AND POSTDOCTORAL STUDIES (Zoology) THE UNIVERSITY OF BRITISH COLUMBIA (Vancouver) May 2016 © Santiago David, 2016 Abstract The high species richness of antbirds (Thamnophilidae) in Amazonian lowlands, where as many as 40 species may coexist at local scales, represents a major challenge for ecologists to explain patterns of coexistence and niche evolution. I studied the foraging ecology of a local community of antbirds in a 2-Km2 area of lowland forest in SE Peru to examine how co- occurring antbird species differ in their use of foraging resources, and whether these differences result in niche partitioning at the community level. I also examined whether resource use similarity was related to phylogenetic similarity in this local assemblage. Forty-four species of antbirds were detected in the study plot in a four-year period, with 30 species categorized as the local assemblage of common resident breeders. Multivariate analysis of foraging parameters showed that segregation at two height layers in two types of forest was more important than foraging substrates and maneuvers in explaining the differences observed in foraging behavior. However, a null model analysis revealed that at the community level, antbirds exhibited high foraging niche overlap, with average observed overlap significantly larger than expected by chance, indicating that antbirds prefer, rather than avoid, resources used by other species.
  • Pine-Oak-Hemlock--Silviculture Institute 7/18/2017 1

    Pine-Oak-Hemlock--Silviculture Institute 7/18/2017 1

    Pine‐Oak‐Hemlock‐‐Silviculture Institute 7/18/2017 Predicted Responses of Wildlife to Silvicultural Treatments with special focus on Pine‐Oak‐Hemlock Types Matt Tarr Associate Extension Professor, Wildlife Specialist University of New Hampshire Cooperative Extension Northeast Silviculture Institute for Foresters June 18, 2017 What am I talking about? OUTLINE • Overview of the primary factors that determine how wildlife respond to timber harvesting • Overview of how birds, mammals, reptiles & amphibians select their habitat • Summary of expected wildlife response following application of silvicultural treatments in pine‐oak‐hemlock MY GOAL: Help you become better at predicting how wildlife will respond to the decisions you make when managing forested habitats 1 Pine‐Oak‐Hemlock‐‐Silviculture Institute 7/18/2017 When we cut trees, the response by wildlife is determined primarily by: • Plant species • Plant structure composition following the harvest • The size of the canopy opening • Whether soils are • Presence/absence of • Habitats in the dry/moist/wet special habitat features surrounding landscape “Plant structure” = presence & density of plants in each forest layer • What plant layers are present? Canopy layer >30’ Midstory layer 10-30’ Shrub layer 2-10’ Herbaceous layer 0-2’ • How dense are the plants in each layer? SPARSE INTERMEDIATE ABUNDANT/DENSE < 30% coverage 30-75% coverage > 75% coverage 2 Pine‐Oak‐Hemlock‐‐Silviculture Institute 7/18/2017 Role of plant structure in influencing wildlife use of forest stands Forest stands comprised
  • Foraging Behavior and Habitat Selection of Insectivorous Migratory Songbirds at Gulf Coast Stopover Sites in Spring

    Foraging Behavior and Habitat Selection of Insectivorous Migratory Songbirds at Gulf Coast Stopover Sites in Spring

    Louisiana State University LSU Digital Commons LSU Historical Dissertations and Theses Graduate School 1996 Foraging Behavior and Habitat Selection of Insectivorous Migratory Songbirds at Gulf Coast Stopover Sites in Spring. Chao-chieh Chen Louisiana State University and Agricultural & Mechanical College Follow this and additional works at: https://digitalcommons.lsu.edu/gradschool_disstheses Recommended Citation Chen, Chao-chieh, "Foraging Behavior and Habitat Selection of Insectivorous Migratory Songbirds at Gulf Coast Stopover Sites in Spring." (1996). LSU Historical Dissertations and Theses. 6323. https://digitalcommons.lsu.edu/gradschool_disstheses/6323 This Dissertation is brought to you for free and open access by the Graduate School at LSU Digital Commons. It has been accepted for inclusion in LSU Historical Dissertations and Theses by an authorized administrator of LSU Digital Commons. For more information, please contact [email protected]. INFORMATION TO USERS This manuscript has been reproduced from the microfilm master. UMI films the text directly from the original or copy submitted. Thus, some thesis and dissertation copies are in typewriter face, while others may be from any type of computer printer. The quality of this reproduction is dependent upon the quality of the copy submitted. Broken or indistinct print, colored or poor quality illustrations and photographs, print bleedthrough, substandard margins, and improper alignment can adversely affect reproduction. In the unlikely event that the author did not send UMI a complete manuscript and there are missing pages, these will be noted. Also, if unauthorized copyright material had to be removed, a note will indicate the deletion. Oversize materials (e.g., maps, drawings, charts) are reproduced by sectioning the original, beginning at the upper left-hand comer and continuing from left to right in equal sections with small overlaps.
  • A Description of Mixed-Species Insectivorous Bird Flocks in Western Mexico’

    A Description of Mixed-Species Insectivorous Bird Flocks in Western Mexico’

    The Condor 89~282-292 0 The Cooper Omithologml Society 1987 A DESCRIPTION OF MIXED-SPECIES INSECTIVOROUS BIRD FLOCKS IN WESTERN MEXICO’ RICHARD L. HUTTO Department of Zoology, Universityof Montana, Missoula, MT 59812 Abstract. Insectivorousbird flockswere observed in all typesof forestedhabitats during the nonbreedingseason in westernMexico. The speciescomposition of flockschanged markedlyand predictablyamong five categoriesof habitat type. The averagenumber of speciesper flockin lowlandhabitats was 4.7, while a mean of 18.6 speciesparticipated in highlandflocks, ranking the latter amongthe most species-richflocks in the world. The meanproportion of the localinsectivorous species that participatedin mixed-speciesflocks wassignificantly greater in the highlands(6 1.3%)than in the lowlands(24.6%). About half of the flock participantsin both undisturbedlowland and highlandhabitats were north temperatemigrants, ranking west Mexican flocks among the mostmigrant-rich in the world as well. In highlandflocks, the maximum numberof individualsper attendantspecies was generallytwo to three,but therewere often six to twelveindividuals belonging to eachof severalnuclear species. The lowlanddeciduous forest flocks seemed to lack nuclearspecies. Key words: Mixed-speciesflocks; insectivorousbirds; Mexico; migratory birds;pine-oak woodlands;tropical deciduous forests. INTRODUCTION mixed-speciesflocks in 26 sites(Appendix I) that Mixed-speciesinsectivorous bird flockshave been were distributed among various habitats described from temperate and tropical areas throughout western Mexico. The habitat types worldwide (Rand 1954), and are known to occur that I surveyed can be roughly classified (after in practically every habitat type (Powell 1985). Pesman 1962) as belonging to either lowland Although mixed-species flocks are quite com- (tropical deciduous and tropical evergreen) or mon in north temperate regions during the non- highland (oak, pine-oak, and boreal) forests.
  • Ecology, Morphology, and Behavior in the New World Wood Warblers

    Ecology, Morphology, and Behavior in the New World Wood Warblers

    Ecology, Morphology, and Behavior in the New World Wood Warblers A dissertation presented to the faculty of the College of Arts and Sciences of Ohio University In partial fulfillment of the requirements for the degree Doctor of Philosophy Brandan L. Gray August 2019 © 2019 Brandan L. Gray. All Rights Reserved. 2 This dissertation titled Ecology, Morphology, and Behavior in the New World Wood Warblers by BRANDAN L. GRAY has been approved for the Department of Biological Sciences and the College of Arts and Sciences by Donald B. Miles Professor of Biological Sciences Florenz Plassmann Dean, College of Arts and Sciences 3 ABSTRACT GRAY, BRANDAN L., Ph.D., August 2019, Biological Sciences Ecology, Morphology, and Behavior in the New World Wood Warblers Director of Dissertation: Donald B. Miles In a rapidly changing world, species are faced with habitat alteration, changing climate and weather patterns, changing community interactions, novel resources, novel dangers, and a host of other natural and anthropogenic challenges. Conservationists endeavor to understand how changing ecology will impact local populations and local communities so efforts and funds can be allocated to those taxa/ecosystems exhibiting the greatest need. Ecological morphological and functional morphological research form the foundation of our understanding of selection-driven morphological evolution. Studies which identify and describe ecomorphological or functional morphological relationships will improve our fundamental understanding of how taxa respond to ecological selective pressures and will improve our ability to identify and conserve those aspects of nature unable to cope with rapid change. The New World wood warblers (family Parulidae) exhibit extensive taxonomic, behavioral, ecological, and morphological variation.
  • Southern Wing-Banded Antbird, Myrmornis Torquata Myrmornithinae

    Southern Wing-Banded Antbird, Myrmornis Torquata Myrmornithinae

    Thamnophilidae: Antbirds, Species Tree I Northern Wing-banded Antbird, Myrmornis stictoptera ⋆Southern Wing-banded Antbird, Myrmornis torquata ⋆ Myrmornithinae Spot-winged Antshrike, Pygiptila stellaris Russet Antshrike, Thamnistes anabatinus Rufescent Antshrike, Thamnistes rufescens Guianan Rufous-rumped Antwren, Euchrepomis guianensus ⋆Western Rufous-rumped Antwren, Euchrepomis callinota Euchrepomidinae Yellow-rumped Antwren, Euchrepomis sharpei Ash-winged Antwren, Euchrepomis spodioptila Chestnut-shouldered Antwren, Euchrepomis humeralis ⋆Stripe-backed Antbird, Myrmorchilus strigilatus ⋆Dot-winged Antwren, Microrhopias quixensis ⋆Yapacana Antbird, Aprositornis disjuncta ⋆Black-throated Antbird, Myrmophylax atrothorax ⋆Gray-bellied Antbird, Ammonastes pelzelni MICRORHOPIINI ⋆Recurve-billed Bushbird, Neoctantes alixii ⋆Black Bushbird, Neoctantes niger Rondonia Bushbird, Neoctantes atrogularis Checker-throated Stipplethroat, Epinecrophylla fulviventris Western Ornate Stipplethroat, Epinecrophylla ornata Eastern Ornate Stipplethroat, Epinecrophylla hoffmannsi Rufous-tailed Stipplethroat, Epinecrophylla erythrura White-eyed Stipplethroat, Epinecrophylla leucophthalma Brown-bellied Stipplethroat, Epinecrophylla gutturalis Foothill Stipplethroat, Epinecrophylla spodionota Madeira Stipplethroat, Epinecrophylla amazonica Roosevelt Stipplethroat, Epinecrophylla dentei Negro Stipplethroat, Epinecrophylla pyrrhonota Brown-backed Stipplethroat, Epinecrophylla fjeldsaai ⋆Napo Stipplethroat, Epinecrophylla haematonota ⋆Streak-capped Antwren, Terenura
  • Patch Utilization by Migrating Birds: Resource Oriented?

    Patch Utilization by Migrating Birds: Resource Oriented?

    ORNISSCANDINAVICA 17: 165-174. Copenhagen1986 Patch utilization by migrating birds: resource oriented? Thomas E. Martin and James R. Karr Martin T. E. and Karr, J. R. 1986. Patch utilization by migrating birds: resource ori- ented? - Ornis Scand. 17: 165-174. Use of gap (created by tree falls) and non-gap forest understory sites by migrating birds in central Illinois was studied during spring and autumn for three years (1978- 1980). Fruit and understory foliage were concentrated in gaps. Birds that relied on these resources (foliage-gleaning insectivores, frugivores in autumn) used gaps more than non-gaps. Birds that fed on food other than fruit and foliage insects ("frugi- vores" in spring, other insectivores) did not use gaps more than non-gaps. Bird abundance varied markedly among gap and non-gap sites, potentially reflecting differences in site preferences. Site selection, as determined by bird abundances, was consistent (correlated) between years for birds that fed on items that were concen- trated in gaps but not for birds that did not rely on these patchy resources. Foliage density is a measure of foraging substrates for foliage-gleaning birds to search. Abun- dance of foliage-gleaning insectivores was highly correlated with foliage density in both spring and autumn. Frugivore abundance was highly correlated with fruiting fo- liage density during autumn when they are frugivorous, but not during spring when they are insectivorous. Insectivores not relying on foliage insects or fruit were un- correlated with either index of resource availability. These same relationships hold even when examining gap sites only. Thus, migrants can be consistent in their se- lection of foraging sites and this consistency appears to exist when resource densities are markedly different among sites (patchy) but not when resources are more disper- sed.
  • The Role of Habitat Variability and Interactions Around Nesting Cavities in Shaping Urban Bird Communities

    The Role of Habitat Variability and Interactions Around Nesting Cavities in Shaping Urban Bird Communities

    The role of habitat variability and interactions around nesting cavities in shaping urban bird communities Andrew Munro Rogers BSc, MSc Photo: A. Rogers A thesis submitted for the degree of Doctor of Philosophy at The University of Queensland in 2018 School of Biological Sciences Andrew Rogers PhD Thesis Thesis Abstract Inter-specific interactions around resources, such as nesting sites, are an important factor by which invasive species impact native communities. As resource availability varies across different environments, competition for resources and invasive species impacts around those resources change. In urban environments, changes in habitat structure and the addition of introduced species has led to significant changes in species composition and abundance, but the extent to which such changes have altered competition over resources is not well understood. Australia’s cities are relatively recent, many of them located in coastal and biodiversity-rich areas, where conservation efforts have the opportunity to benefit many species. Australia hosts a very large diversity of cavity-nesting species, across multiple families of birds and mammals. Of particular interest are cavity-breeding species that have been significantly impacted by the loss of available nesting resources in large, old, hollow- bearing trees. Cavity-breeding species have also been impacted by the addition of cavity- breeding invasive species, increasing the competition for the remaining nesting sites. The results of this additional competition have not been quantified in most cavity breeding communities in Australia. Our understanding of the importance of inter-specific interactions in shaping the outcomes of urbanization and invasion remains very limited across Australian communities. This has led to significant gaps in the understanding of the drivers of inter- specific interactions and how such interactions shape resource use in highly modified environments.
  • Appendix H: Birds Specialist Report

    Appendix H: Birds Specialist Report

    Report No: P WMA 19/G10/00/2413/3 Department of Water Affairs Directorate: Options Analysis PRE-FEASIBILITY AND FEASIBILITY STUDIES FOR AUGMENTATION OF THE WESTERN CAPE WATER SUPPLY SYSTEM BY MEANS OF FURTHER SURFACE WATER DEVELOPMENTS REPORT No.1 – VOLUME 3 Berg Estuary Environmental Water Requirements APPENDIX No.H Specialist Report - Birds June 2012 STUDY REPORT LIST DWA REPORT VOLUME REPORT TITLE REPORT VOLUME TITLE No No. No. Riverine Environmental Water Requirements Appendix 1: EWR data for the Breede River Appendix 2: EWR data for the Palmiet River PWMA19 Vol 1 G10/00/2413/1 Appendix 3: EWR data for the Berg River Appendix 4: Task 3.1: Rapid Reserve assessments (quantity) for the Steenbras, Pombers and Kromme Rivers Appendix 5: Habitat Integrity Report – Breede River Rapid Determination of the Environmental Water Requirements of the Palmiet River Estuary Appendix A: Summary of data available for the RDM investigations PWMA19 Vol 2 undertaken during 2007 and 2008 G10/00/2413/2 Appendix B: Summary of baseline data requirements and the long- ECOLOGICAL term monitoring programme WATER 1 REQUIREMENT Appendix C: Abiotic Specialist Report ASSESSMENTS Berg Estuary Environmental Water Requirements Appendix A: Available information and data Appendix B: Measurement of streamflows in the Lower Berg downstream of Misverstand Dam Appendix C: Specialist Report – Physical dynamics and water quality PWMA19 Appendix D: Specialist Report – Modelling Vol 3 G10/00/2413/3 Appendix E: Specialist Report – Microalgae Appendix F: Specialist Report – Invertebrates
  • Bark-Foragers May Use Artificially Created Holes in Trees As a Foraging Cue Ruby L

    Bark-Foragers May Use Artificially Created Holes in Trees As a Foraging Cue Ruby L

    Arizona Birds - Journal of Arizona Field Ornithologists Volume 2020 BARK-FORAGERS MAY USE ARTIFICIALLY CREATED HOLES IN TREES AS A FORAGING CUE RUBY L. HAMMOND, YAZHMIN A. DOZAL, AND TAD C. THEIMER, DEPARTMENT OF BIOLOGICAL SCIENCES, NORTHERN ARIZONA UNIVERSITY, FLAGSTAFF, AZ, 86011, [email protected] ABSTRACT: Little is known about cues used by insectivorous bark-foraging birds to locate prey. Because vision is thought to be the primary sensory system used by many avifauna to perceive the environment, we conducted an experiment to assess if insectivorous bark-foragers in northern Arizona forests used holes in trees as foraging cues. We set up 20 experimental stations, each consisting of a pair of equally sized ponderosa pines (Pinus ponderosa) that had no previous holes created by foraging woodpeckers or emergent boring-beetles. For each pair of trees, we drilled holes into one of the trees (treatment tree) and did not drill holes into the other (control tree). We monitored trees using trail cameras and reviewed photographs to determine: 1) at each station, was the first landing by each bark-foraging species on a treatment or control tree; and 2) how much time did bark-foragers spend on treatment vs. control trees? The experiment supported our hypothesis that bark-foragers used holes in trees as foraging cues. Twelve of 16 first-landing events were on treatment trees (χ21 = 4.0, p < 0.05), and 28 of 43 total photographs of bark- foragers were on treatment trees (χ21 = 3.9, p < 0.05). This experimental assessment of a visual foraging cue used by bark-foraging birds in the wild suggested that this guild may use holes created by woodpeckers or boring-beetles and larvae as a foraging cue.