Differences in home-range sizes of a bird species in its original,refuge and substitution habitats: challenges to conservation in anthropogenic habitats

In the current context of the anthropocene, the original habitats of many species have been modified or destroyed. Animals may be forced to move from their original habitats, either to refuge habitats that are suboptimal natural habitats, or to substitution habitats that are anthropogenic. The quality of refuge habitats may be lower than that of the original ones, whereas substitution habitats may be of a similar or even better quality. Here, we test this hypothesis empirically, using the example of coastal populations of the bluethroat, Luscinina svecica namnetum. In a radio-tracking survey, we compared the home-range sizes (considered here a proxy of habitat quality) of the breeding males in their original (coastal saltmarshes), refuge (inland reedbeds) and substitution (coastal salinas) habitats. We found that home ranges are up to 15 times larger in the substitution habitat than in the original one, and intermediate in the refuge habitat, suggesting that substitution habitats have the lowest quality and original habitats the highest. To date, most studies and conservation programs related to this species have focused on its substitution habitats. This result challenges the interest of focusing on anthropogenic habitats when studying and conserving such a species, because such habitats may only be low-quality substitutes.     

Freshwater sponge (Porifera: Spongillidae) distribution across a landscape: Environmental tolerances,habitats, and morphological variation

Freshwater sponges are important to ecosystem functioning; however, information about their biogeography and interspecific variation is fragmentary, limiting our ability to assess their role. Although the specific epithets of two common species suggest that sponges found in lentic habitats are Spongilla lacustris, and those found in lotic habitats are Ephydatia fluviatilis, the number of sponge species in the UK is unresolved. We sampled sponges in a variety of habitats and used both morphological and molecular (D3 domain of 28S rDNA) methods to identify six species, including the first record of Trochospongilla horrida. We contrasted species in terms of their environmental tolerances, habitats, and variation, and we expanded on the limited information available about the geographic distributions of these sponges. In our study, most sponge species colonized a variety of substrates, but exhibited different distributions. The most widespread sponge, S. lacustris, was present at lower mean water temperatures and was more often located above a latitude of 55°N. Ephydatia fluviatilis was the most common species in rivers, but was also located in lentic habitats. Salinity in anthropogenic habitats was not a significant factor for the presence of E. fluviatilis or the more patchily distributed species Eunapius fragilis. Instead, these species occurred more frequently at sites with negative oxidation–reduction potential. Sponge biodiversity may be affected by substrate availability in anthropogenic habitats, invasive species, and improved ability to recognize sponge taxa. Crucially, we provide foundation data as a prerequisite for future ecological evaluation.     

Human altered ecosystems: suitable habitats as well as ecological traps for dragonflies (Odonata): the matter of scale

Habitat loss and degradation can be considered as major threats to freshwater invertebrates. These often irreversible processes lead to reduction of habitat patch quality and cause local extinctions of dragonflies, notably of habitat specialists. However, the biodiversity of specific secondary habitats is very high. Here, we present findings from a 10-year study that intensively monitored odonate fauna in the Upper Silesian industrial coal region having many secondary habitats characterized by very frequent disturbances due to soil instability. We evaluated qualitative changes in the dragonfly assemblages on 10 patches using a modified dragonfly biotic index. Data analysis was supplemented by a model examining population dynamics of the threatened dragonfly Leucorrhinia pectoralis, using the capture-mark-recapture method, as an effective indicator of habitat quality. We show that dynamics of environmental conditions in secondary habitats are reflected in population dynamics of dragonfly populations and assemblages. As frequency of L. pectoralis population extinctions within the patch is considerable and independent of size and spatial isolation of single habitats, these can be regarded as ecological traps. Nevertheless, the metapopulation dynamics may be a key adaptation of dragonflies to frequent freshwater habitat disturbances. We suggest that local extinctions are effectively balanced with (re-)colonization of newly emerging freshwater habitats. These findings have implications for potential conservation management of specific human-made habitats, because secondary habitats with a great diversity of succession stages arising directly as a consequence of environmental instability may be considered as partial alternatives to natural habitats in cultural landscapes.     

Habitat selection by nocturnal passerine migrants en route: mechanisms and results

Habitat use and habitat selection are essential for successful stopovers. Passerine migrants use habitats in a clearly non-random manner, even if many species utilise a broader range of habitats during passage than during breeding or wintering. Habitat selection proceeds as a sequence of events: landfall; search/settling, including redistribution across habitats if necessary; and habitat exploitation, with all stages probably condition-dependent. This review is aimed at studying this sequence and also the factors which govern decision-making in nocturnal passerine migrants at all levels. In most cases, habitats are (pre)selected by migrants already at landfall using both visual and acoustic cues. After landfall, migrants start to perform direct sampling of habitats during which they may move constantly and perform fine-tuning of their habitat choice. Some species subsequently occupy a small home range in a particular (micro)habitats, whereas others continue to move broadly during the whole stopover period. An interaction of several factors shapes the use of habitats after landing, among which are migrants’ innate preferences and functional morphology, foraging strategies and food resource distribution, habitat carrying capacity and exposure to predators. The large-scale spatial context probably also plays a role which might be currently underestimated.     

The Mangrove Nursery Paradigm Revisited: Otolith Stable Isotopes Support Nursery-to-Reef Movements by Indo-Pacific Fishes

Mangroves and seagrass beds have long been perceived as important nurseries for many fish species. While there is growing evidence from the Western Atlantic that mangrove habitats are intricately connected to coral reefs through ontogenetic fish migrations, there is an ongoing debate of the value of these coastal ecosystems in the Indo-Pacific. The present study used natural tags, viz. otolith stable carbon and oxygen isotopes, to investigate for the first time the degree to which multiple tropical juvenile habitats subsidize coral reef fish populations in the Indo Pacific (Tanzania). Otoliths of three reef fish species (Lethrinus harak, L. lentjan and Lutjanus fulviflamma) were collected in mangrove, seagrass and coral reef habitats and analyzed for stable isotope ratios in the juvenile and adult otolith zones. δ¹³C signatures were significantly depleted in the juvenile compared to the adult zones, indicative of different habitat use through ontogeny. Maximum likelihood analysis identified that 82% of adult reef L. harak had resided in either mangrove (29%) or seagrass (53%) or reef (18%) habitats as juveniles. Of adult L. fulviflamma caught from offshore reefs, 99% had passed through mangroves habitats as juveniles. In contrast, L. lentjan adults originated predominantly from coral reefs (65–72%) as opposed to inshore vegetated habitats (28–35%). This study presents conclusive evidence for a nursery role of Indo-Pacific mangrove habitats for reef fish populations. It shows that intertidal habitats that are only temporarily available can form an important juvenile habitat for some species, and that reef fish populations are often replenished by multiple coastal habitats. Maintaining connectivity between inshore vegetated habitats and coral reefs, and conserving habitat mosaics rather than single nursery habitats, is a major priority for the sustainability of various Indo Pacific fish populations.     

Getting in shape: habitat‐based morphological divergence for two sympatric fishes

Freshwater fishes often show large amounts of body shape variation across divergent habitats and, in most cases, the observed differences have been attributed to the environmental pressures of living in lentic or lotic habitats. Previous studies have suggested a distinct set characters and morphological features for species occupying each habitat under the steady–unsteady swimming performance model. We tested this model and assessed body shape variation using geometric morphometrics for two widespread fishes, Goodea atripinnis (Goodeidae) and Chirostoma jordani (Atherinopsidae), inhabiting lentic and lotic habitats across the Mesa Central of Mexico. These species were previously shown to display little genetic variation across their respective ranges. Our body shape analyses reveal morphometric differentiation along the same axes for both species in each habitat. Both possess a deeper body shape in lentic habitats and a more streamlined body in lotic habitats, although the degree of divergence between habitats was less for C. jordani. Differences in the position of the mouth differed between habitats as well, with both species possessing a more superior mouth in lentic habitats. These recovered patterns are generally consistent with the steady–unsteady swimming model and highlight the significance of environmental forces in driving parallel body shape differences of organisms in divergent habitats. © 2014 The Linnean Society of London, Biological Journal of the Linnean Society, 2014, 114 , 152–162.     

Source-sink populations in Mediterranean Blue tits: evidence using single-locus minisatellite probes

Long term studies on population biology of Blue tits (Parus caeruleus L.) in Mediterranean habitats have shown that in patchy landscapes life-history traits seem to be adapted to the predominant type of habitat, where reproductive success is higher. The “source-sink hypothesis” suggests that differences in the local production of fledglings result in an asymmetrical gene flow from rich deciduous habitats (“source”) to evergreen poor habitats (“sink”), preventing local adaptation in evergreen habitats. In this study we used single-locus minisatellite DNA probes to test the following predictions of the source-sink hypothesis: 1) source and sink populations are not genetically differentiated; 2) amount of gene flow is ranked in the following decreasing order: between source and sink habitats, among source habitats and among sink habitats; and 3) linkage disequilibrium is higher in sink than in source populations. Results were consistent with these three predictions, and with previous results obtained using other approaches. Results clearly support a source-sink functioning of Blue tit populations in southern France mosaic landscapes, and emphasise the need of combining genetic and ecological studies to understand the functioning of natural populations.     

Terrestrial flatworm (Platyhelminthes: Tricladida: Terricola) diversity versus man-induced disturbance in an ombrophilous forest in southern Brazil

Terrestrial flatworms, or Terricola, are sensitive to environmentalchanges and therefore might be excellent indicators of the conservation statusof natural habitats. The present study aimed to answer two main questions: (1)is terrestrial planarian diversity affected by human disturbances, and (2) isthere any species or group of species that indicates such disturbance? The studysite, National Forest of São Francisco de Paula, Brazil, was originallycovered by a mixed ombrophilous forest, but successive reforestations andselective logging have modified the original landscape. We studied Terricoladiversity in the four main habitats in the study area: mixed ombrophilous forest(NA), ombrophilous forest with selective Araucariaangustifolia logging (N), A. angustifoliareforestation (A), and reforestation of Pinus elliottii(P). According to an increasing degree of disturbance, the habitats might beordered as follows: (NA)<(N)<(A)<(P). We conducted 24 surveys in eachhabitat over a period of 1 year. Our results indicate that: (1)Terricola diversity is inversely related to the degree of habitat disturbance;(2) there are species (Geoplana franciscana,Geoplana sp. 5, and possibly Geoplanidae 3 andNotogynaphallia guaiana) that prefer habitats located onthe extreme right along the main axis of a detrended correspondence analysisordination and therefore can be considered as indicators of well preserved,natural habitats. On the other hand there are species(Xerapoa sp. 1, Choeradoplanaiheringi, G. marginata sensu Marcus andGeoplana sp. 2) preferring more disturbed habitats, whichmay form biological indicators of such disturbances.     

Habitat size thresholds for predators: Why damselflies only occur in large bromeliads

Predators are often more sensitive to habitat size than their prey and frequently occur in only the largest habitats. Four explanations have been proposed for this pattern: (a) Small habitats do not have enough energy to support higher trophic levels; (b) small habitats are less likely to contain particular prey required by specialist predators; (c) small habitats are risky for predators with slow life histories or large body sizes; and (d) small habitats are numerically unlikely to be colonized by regionally rare species, such as predators. We critically examine these four hypotheses in relation to the predatory damselfly larva, Mecistogaster modesta Selys. (Pseudostigmatidae), which occurs almost exclusively in bromeliads > 100ml in capacity. We synthesize multiple years of survey data and three manipulative experiments from the Área de Conservación Guanacaste, Costa Rica, to conclude that damselflies do not occur in small bromeliads due to their higher risk of desiccation—not because of energetic limitation, trophic specialization, risk of terrestrial predation, or pure numerical effects. These results suggest that recent and predicted declines in precipitation in northwestern Costa Rica may further restrict bromeliad occupancy by damselflies, with cascading consequences for the rest of the aquatic food web.     

Prioritization of natural habitats: A methodological framework applied to the French Mediterranean

Long-term preservation of habitats has become a cornerstone of modern conservation policies. As resources allocated to conservation actions are often limited, developing relevant prioritizing methods is necessary. Although many studies have been published on species prioritization, habitats have been the subject of less research. This study aims to develop a simple prioritization method suitable for habitats and appropriate to any typology. We analyzed literature to select criteria that would be the most accurate to rank habitats. Our final method consists in calculating a score based on four criteria: legal obligation, territorial responsibility, conservation condition and an extra criterion designed to fit local interests and objectives. The method is applied on habitats listed in Annex I of the Habitats Directive (92/43/EEC) on the territory of RESEDA-Flore, a network of stakeholders involved in the conservation of Mediterranean flora. Results highlight that dune habitats show the highest conservation values, while rocky habitats and caves obtain relatively low scores. At the top of the ranking, Mediterranean temporary ponds (3170), Dunes with Pinus pinea and/or Pinus pinaster forests (2270) and Coastal dunes with Juniperus spp. (2250) appear to be a high priority. These results can be used to design and implement habitat conservation strategies in the French Mediterranean.     

Global diversity of oribatids (Oribatida: Acari: Arachnida)

Oribatid mites are primarily terrestrial. Only about 90 species (less than 1% of all known oribatid species) from 10 genera are truly aquatic, with reproduction and all stages of their life cycle living in freshwater. Adaptation to aquatic conditions evolved independently in different taxa. However, many terrestrial species can also be found in aquatic habitats, either as chance stragglers from the surrounding habitats, or from periodic or unpredictable floodings, where they can survive for long periods. In spite of their low species richness aquatic oribatids can be very abundant in different freshwater habitats as in lentic (pools, lakes, water-filled microhabitats) or flowing waters (springs, rivers, streams), mainly on submerged plants. The heavily sclerotized exoskeletons of several species enables subfossil or fossil preservation in lakes or bog sediments. Guest editors: E. V. Balian, C. Lévêque, H. Segers & K. Martens Freshwater Animal Diversity Assessment     

Habitat complexity and the structure of vocalizations: a test of the acoustic adaptation hypothesis in three rail species (Rallidae)

The acoustic adaptation hypothesis is based on the assumption that senders are directionally selected to maximize transmission and minimize degradation; however, the two aims are not necessarily convergent. In complex habitats, where more effects that might potentially cause attenuation and degradation co‐occur and longer transmission must incur a higher cost, signals should attenuate faster and have shorter transmission ranges. At the same time, such signals should be more resistant to degradation in order to preserve their communicatory function. Based on a sound transmission experiment, we tested the evidence for these predictions using territorial calls of three sympatric species of rails, inhabiting habitats with increasing complexity: Corncrake Crex crex, Spotted Crake Porzana porzana and Water Rail Rallus aquaticus. In the experiment, the calls were broadcasted with similar amplitudes through a heterogeneous habitat inhabited by all three species and rerecorded at different distances up to 320 m. Despite standardized amplitudes and habitats, calls of the species living in simpler habitats had longer transmission ranges but were more susceptible to degradation than calls of the species living in more complex habitats. Our results suggest that narrow frequency bandwidth is an adaptation of species inhabiting complex habitats that helps their calls to degrade less at the cost of stronger attenuation and shorter transmission range. By contrast, wide frequency bandwidth extends the range but increases degradation and thus it is used only by species inhabiting structurally simpler habitats. This study shows that, in more complex habitats, the clarity of the message is preserved at the cost of range.     

The species diversity of New Zealand forest birds: Some possible consequences of the modification of beech forests

The literature on forest birds in New Zealand is examined to see if the consequences of forest modification can be predicted. Forty‐four samples of birds, from North, South, and Stewart Islands, are classified according to four habitats of origin: virgin forest, modified forest, exotic forest, and suburban bush and gardens. An index of bird species diversity (BSD) is calculated for comparison, and where possible densities are tabulated.

Limited samples from modified forests in Westland suggest that the number of species is relatively smaller but the bird density is higher after modification. There do not seem to be any published quantitative data about birds in Westland exotic forests.

Data from the whole of New Zealand show that bird density increases as forest habitats change from virgin, to modified, to exotic, to suburban bush and gardens. BSD and equitability do not differ among these habitats. The number of species of native birds and their diversity decline as the habitat is more extensively altered, but their total density tends to remain constant. More productive forest habitats have the same BSD as other habitats. Diversity seems to be limited by the small variety of bird species available, and the more productive habitats could probably support more species. All habitats had a much higher diversity of birds before colonisation by the European.     

Marine mites (Halacaroidea: Acari): a geographical and ecological survey

Halacarid mites (Acari), with almost 700 species described, inhabit marine and freshwater habitats. The majority of genera are recorded from at least two ocean basins or continents. There is no evidence of endemic genera, in either littoral faunal provinces or in deep-sea regions. Copidognathus, a genus comprising 1/4 of all species described, is found in almost all geographic regions, depths and habitats. Other genera dominate or are restricted to cold waters, to warm waters or to distinct habitats.Corresponding habitats on either side of the boreal Atlantic Ocean harbour congeneric, identical, sibling or morphologically similar species. The fauna in the western Atlantic is less diverse than that in the eastern. Amphiatlantics are restricted to certain genera. Transatlantic distribution is independent of the niche inhabited.Of the marine halacarid species recorded from the boreal western Atlantic, 41% are amphiatlantics, while only one species is recorded from both the Caribbean and the Mediterranean. The Caribbean and the Mediterranean faunas are dominated by genera in which amphiatlantics are unknown.Most of the Black Sea species of the genus Halacarellus also occur in the Baltic, North Sea or North Atlantic, whereas the Copidognathus fauna of the Black Sea is similar to that of the Mediterranean.Halacarids are thought to be an ancient taxon, with most genera probably having been present since the Mesozoic and with several species having an age of at least 50 million years. Evidence for their antiquity is found in the distributional pattern of marine and limnic genera and species, in the lack of endemic genera despite low fecundity and lack of dispersal stages, and in the fact that amphiatlantics are restricted to certain genera without relationships to the niches inhabited.     

Seedling establishment,mortality, tree growth rates and vigour of Acacia nilotica in different Astrebla grassland habitats: Implications for invasion

A demographic study was conducted in the northern Australian Astrebla grasslands to determine the importance of habitat type in influencing invasion patterns of Acacia nilotica, an exotic leguminous tree from Africa and Asia. One of the repeated patterns observed for A. nilotica is that denser populations are often associated with riparian habitats. Data available on this species do not enable us to determine which of a number of processes has lead to the formation of this pattern. Several explanations were tested for patterns in tree abundance: (i) that more seedlings emerge in wetter habitats; (ii) that mortality is lower in wetter habitats; (iii) that growth rates are faster in wetter habitats; and (iv) that plants are more vigorous (as indicated by leaf cover, flowering intensity and predation rates) over longer periods in wetter habitats. The study was stratified across three habitat types, perennial and ephemeral riparian and non‐riparian, which are characteristic of Astrebla grasslands and differentiated by the availability of water. In addition to testing for habitat‐linked differentiation in demography, data were also used to test whether seedling emergence, mortality, growth and vigour varied between sites with cattle versus sheep. The data collected indicated that seedling emergence, determined primarily by livestock dispersal, was likely to be the dominant influence on patterns of A. nilotica invasion. Mortality and growth rates were similar in ephemeral riparian and non‐riparian habitats, whereas perennial riparian habitats had more rapid growth rates, which may increase the rate of invasion in these areas. Plant vigour was also greater over longer periods in perennial riparian habitats with greater leaf cover, longer flowering season and fewer insect borer holes. Livestock species were found to have little influence on the demography of A. nilotica plants in this study. Very low growth rates and high mortality in A. nilotica populations are likely to lead to net decline in ephemeral riparian and non‐riparian habitats in the long term. The importance of episodic recruitment in the maintenance of A. nilotica populations is discussed.     

Fish Brains: Evolution and Anvironmental Relationships

Fish brains and sensory organs may vary greatly between species. With an estimated total of 25 000 species, fish represent the largest radiation of vertebrates. From the agnathans to the teleosts, they span an enormous taxonomic range and occupy virtually all aquatic habitats. This diversity offers ample opportunity to relate ecology with brains and sensory systems. In a broadly comparative approach emphasizing teleosts, we surveyed classical and more recent contributions on fish brains in search of evolutionary and ecological conditions of central nervous system diversification. By qualitatively and quantitatively comparing closely related species from different habitats, particularly cyprinids and African cichlids, we scanned for patterns of divergence. We examined convergence by comparing distantly related species from similar habitats, intertidal and deep-sea. In particular, we asked how habitats relate to the relative importance of different sensory faculties. Most fishes are predominantly visually orientated. In addition, lateral line and hearing are highly developed in epi- and mesopelagic species as well as in the Antarctic notothenoids. In bathypelagics, brain size and the lobes for vision and taste are greatly reduced. Towards shallow water and deep-sea benthic habitats, chemosenses increase in importance and vision may be reduced, particularly in turbid environments. Shallow tropical marine and freshwater reefs (African lakes) enhance visual predominance and appear to exert a considerable selection pressure towards increased size of the (non-olfactory)telencephalon. The development of cognitive skills (spatial learning, problem solving) in fish seems to be associated with visual orientation and well-structured habitats.     

North American Brant: effects of changes in habitat and climate on population dynamics

We describe the importance of key habitats used by four nesting populations of nearctic brant (Branta bernicla) and discuss the potential relationship between changes in these habitats and population dynamics of brant. Nearctic brant, in contrast to most geese, rely on marine habitats and native intertidal plants during the non‐breeding season, particularly the seagrass, Zostera, and the macroalgae, Ulva. Atlantic and Eastern High Arctic brant have experienced the greatest degradation of their winter habitats (northeastern United States and Ireland, respectively) and have also shown the most plasticity in feeding behavior. Black and Western High Arctic brant of the Pacific Flyway are the most dependent on Zostera, and are undergoing a shift in winter distribution that is likely related to climate change and its associated effects on Zostera dynamics. Variation in breeding propensity of Black Brant associated with winter location and climate strongly suggests that food abundance on the wintering grounds directly affects reproductive performance in these geese. In summer, salt marshes, especially those containing Carex and Puccinellia, are key habitats for raising young, while lake shorelines with fine freshwater grasses and sedges are important for molting birds. Availability and abundance of salt marshes has a direct effect on growth and recruitment of goslings and ultimately, plays an important role in regulating size of local brant populations.     

Plant species occurrences in a rural hemiboreal landscape: effects of remnant habitats, site history, topography and soil

Changes in land use during the last century have caused fragmentation and a reduction in area of many species-rich habitats in the hemiboreal region. We examined abundances of plant species and their occurrence in different habitats in south-east Sweden. We found 361 plant species in 146 sample sites, which represented 14 different types of habitat. Most species were rare and occurred only in a few habitats. Almost half of all species (49%) were found in one or two habitats. Of these, 99 species occurred in one habitat only. The habitats with largest number of restricted species, i.e. habitat specialists, were dry to mesic semi-natural grasslands and remnant habitats such as road verges and mid field islets. The occurrence of 52 species was analysed with respect to topography, top- and subsoil and land use history. Few of the 52 species were affected by aspect or type of topsoil. Subsoil affected nearly half of the species and habitats with a convex landform influenced occurrence of > 90% of the species. Seventeen species were positively associated with a long continuity of grassland management, whereas two species were associated with lack of management. Open grasslands that are encroached by trees and shrubs show a decline in species number. Deciduous forests, especially wet deciduous forests, have a potential for restoring moist to mesic grassland habitats. Small remnant habitats are important for many of the species restricted to semi-natural grasslands. These habitats may function as "rescue sites" for the species, which in turn may promote dispersal and increase likelihood of restoration success. Therefore, remnant habitats are important for maintaining and restoring species richness in rural landscapes.     

The Disturbed Resource-Flux Invasion Matrix: A New Framework for Patterns of Plant Invasion

Attempts to classify certain habitats as vulnerable to invasion or plant traits as invasive have met with limited success and applicability. Clearly, not all plant invaders are able to exploit all habitats and not all habitats are equally susceptible to invasion. Here we argue that it is critical for a successful model for invasions to incorporate both environmental and species traits and present just such a framework. Although disturbance has been targeted as a crucial event which renders habitats vulnerable to invasion, disturbances are often integral parts of ecosystems (e.g. floods, tree-falls, fire, etc.) and are not always associated with invasion events. We argue that disturbances that are associated with invasions alter historical patterns of turnover, or flux, of resources in an ecosystem. Given this perspective on the relationship between invasions and disturbances, and the need to integrate species traits with those of invaded ecosystems, we have developed an approach to characterize plant invasion patterns that we call the Disturbed Resource-Flux Invasion Matrix or DRIM. This is a 16-cell matrix that classifies habitats by the quality of changes in physical and chemical resource flux either increasing or decreasing flux relative to historical patterns. Within each matrix cell, it is then possible to apply basic ecological principles to target species traits that can facilitate successful invasion of habitats experiencing that particular kind of disturbance. We present examples from the literature of how habitats and species can be classified according to the DRIM, and demonstrate the application of this theoretical model.     

Secondary succession and breeding bird community structure: Patterns of resource utilization

Summary Structure of breeding bird communities was compared among four habitat types representative of stages present in most old-field successions in the eastern deciduous forest formation of North America. The successional catagories, defined by vegetational structure, were designated herbaceous (type A habitats) herb, shrub and sapling (type B), young forest (type C), and older forest (type D). Density of breeding birds was lowest in A habitats, rose sharply in B habitats and reached a maximum in D habitats. Species richness and number of feeding guild showed similar patterns. Mean number of species per guilds was highest in D habitats. Generalist feeding guilds were predominant in type A and B habitats, primarily due to the importance of the graminivore-insectivore guild. Specialist guilds increased in importance with succession due to addition of several insectivorous guilds in later successional stages. Patterns of occurrence of individual feeding guilds are analyzed and discussed with respect to changes in vegetational structure. Variance in community structure was generally highest in A habitats and lowest in D habitats; this is discussed in relation to the evolution of saturated, coadapted communities.