John W. Fitzpatrick

Neotropical birds : ecology and conservation

A synthesis of the ecological information on 4037 species of birds found from Mexico south to Tierra del Fuego. This work summarizes details on 40 key ecological parameters for each bird species. Additional data and further analyses are provided for migratory species. Because bird communities are good indicators of habitat type and condition, and because extensive bird surveys can be done quickly, bird communities are critical to rapid evaluations of an ecosystems biological value and integrity. The authors analyze the bird species of major habitats from a conservation perspective, and develop specific guidelines to illustrate how governments, conservation organizations, and wildlife managers can use this ecological information to anchor conservation strategies on sound biological reality.

The Inheritance of Territory in Group-Breeding Birds

Recent advances in animal socioecology stress the importance of kinship and group living in the evolution of social behavior (see Wilson 1975). Although many animals exhibit a relatively simple social system in which individuals disperse and breed upon reaching maturity, among some higher vertebrate species certain individuals regularly delay breeding beyond normal physiological maturity and live for long periods in extended family groups. Group breeding, in which nonbreeding individuals help care for the young of a breeding pair, is now documented for a great variety of birds (Rowley 1976). Of special interest to evolutionary biologists is the question: Why do certain individuals seem to forfeit their own reproductive efforts to assist others with their breeding? Typical of the group breeders studied to date is close genetic relatedness between the helpers and the young they help raise (Brown 1974, Gaston 1976, Hardy 1976, MacRoberts and MacRoberts 1976, Maynard Smith and Ridpath 1972, Rowley 1965, Woolfenden 1975). Furthermore, the presence of helpers has been shown to increase the number of offspring produced by the resident breeders, who usually are parents of the helpers (Rowley 1965, Woolfenden 1975). Thus, by helping to raise kin, a nonbreeder may increase the representation of its own genes in the population without being a parent (Hamilton 1964, West Eberhardt 1975). This has led to the conclusion that kin selection underlies the evolution of helping behavior (Brown 1974, Wilson 1975). Our preliminary work with Florida scrub jays (Aphelocoma c. coerulescens), plus certain data available for other group-breeding birds, suggests the possibility of additional, more direct benefits to the helpers from delaying breeding and helping. Many group-breeding species studied to date occupy mature, often relict habitats, and show many characteristics of intense K-selection (sensu MacArthur and Wilson 1967; Brown 1974, 1975). Competition for space appears to be paramount among these characteristics. This observation, together with the data presented herein, leads us to hypothesize in this paper that, in certain species, remaining home and helping represents a strategy used by nonbreeders to inherit the space necessary for breeding.

Cadmium toxicity among wildlife in the Colorado Rocky Mountains

Cadmium is known to be both extremely toxic and ubiquitous in natural environments. It occurs in almost all soils, surface waters and plants, and it is readily mobilized by human activities such as mining. As a result, cadmium has been named as a potential health threat to wildlife species; however, because it exists most commonly in the environment as a trace constituent, reported incidences of cadmium toxicity are rare. Here we have measured trace metals in the food web and tissues of white-tailed ptarmigan (Lagopus leucurus) in Colorado. Our results suggest that cadmium toxicity may be more common among natural populations of vertebrates than has been appreciated to date and that cadmium toxicity may often go undetected or unrecognized. In addition, our research shows that ingestion of even trace quantities of cadmium can influence not only the physiology and health of individual organisms, but also the demographics and the distribution of species.

Foraging Behavior of Neotropical Tyrant Flycatchers

-An overview of the foraging characteristics of tyrant flycatchers (Tyrannidae) is presented in three parts. First, the physical techniques of different prey capture methods are described, and a standardized nomenclature for these techniques is suggested. Second, ten predominant “foraging modes” are defined according to the comparative frequencies with which each prey capture method is used by different species. Certain species use specialized foraging modes, in that their foraging behavior is confined to a single capture method. Other more generalized foraging modes are characterized by the use of several or many capture methods with similar frequency. Third, the distribution of these foraging modes within the family as a whole is summarized in a genus by genus outline, with genera grouped according to a recent systematic revision of the family. The resulting pattern shows that each of the three subfamilies contains certain behaviorally generalized genera as well as radiations into related, but more specialized, foraging modes. Tyrant flycatchers (Tyrannidae) form one of the largest and most diverse bird families in the world. The 375 species (Traylor 1977) include one tenth of South America’ s entire land bird fauna (Meyer de Schauensee 1966), and their range of body forms and ecological roles is rivaled in the New World only by the Furnariidae (Feduccia 1973). This diversity, coupled with the ubiquity and numerical dominance of tyrannids throughout the Neotropics, makes the family ideally suited for a variety of studies regarding adaptive radiation in a continental avian group. Keast (1972) presented a brief overview of the tyrannid radiation, and several authors have analyzed evolution within selected flycatcher groups in greater depth (e.g., Lanyon 1967, 1978, Smith and Vuilleumier 1971, Fitzpatrick 1976). However, the scarcity of basic information on tyrannid biology, particularly among tropical species, has until now prohibited any comprehensive evaluation of the family’ s radiation. With this paper I initiate a series of reports on ecological and evolutionary trends in the Tyrannidae by describing and classifying the foraging tactics that characterize the family (see also Fitzpatrick 1978). By necessity the bulk of this report is descriptive, my intent being to propose a standard by which tyrannid foraging behavior may be quantitatively described and analyzed from a variety of perspectives (see Discussion). The paper is presented in three sections, beginning with descriptions and suggested nomenclature for each of the prey capture techniques used by flycatchers. This is followed by an outline of the predominant ways that different tyrannids combine these individual techniques into discrete “foraging modes,” each mode represented by a characteristic combination of prey capture techniques. Certain foraging modes are shown to reflect behavioral specialization, while other modes are more generalized. I conclude by reviewing the occurrence of these foraging modes within each of the major phyletic groups in the Tyrannidae, based on my own field studies, published information, and the recent systematic review of the family by Traylor (1977). STUDY SITES AND METHODS Data discussed in this report were accumulated over ten months of field work in an Amazonian forest site in southeastern Peru (Cocha Cashu Biological Station, Manu National Park, dept. Madre de Dios) where 61 tyrannid species have been recorded; two months in extreme northern Peru in a subtropical montane forest (Cordillera de1 Condor, dept. Cajamarca); four months in semi-arid scrub and deciduous forest sites in northwestern Venezuela (Falcon and Aragua); two months in cerrado, campo, and caatinga sites in southeastern and east-central Brasil (Santa Barbara do Rio Pardo. Sao Paulo; Parque National de Brasilia; Exu, Pernambuco). Field work was conducted between June 1974 and September 1977. I was present in southeastern Peru and northern Venezuela during both wet and dry seasons, but worked in northern Peru and in Brasil only during their dry periods, from June to September. I observed 167 flycatcher species in the wild. These represent all three subfamilies (Traylor 1977) and 71 of the 88 currently recognized tyrannid genera. I gathered quantitative data on foraging behavior for 90 tyrannid species at the above-mentioned sites. I watched flycatchers with the naked eye or through 9 x 35 power binoculars, and dictated observations into a portable tape recorder for later transcription. Foraging data were recorded only from individuals I judged to be actively foraging, primarily during morning and late afternoon peaks of activity. Sluggishness, resting, or

Congruent population structure inferred from dispersal behaviour and intensive genetic surveys of the threatened Florida scrub‐jay (Aphelocoma cœrulescens)

The delimitation of populations, defined as groups of individuals linked by gene flow, is possible by the analysis of genetic markers and also by spatial models based on dispersal probabilities across a landscape. We combined these two complimentary methods to define the spatial pattern of genetic structure among remaining populations of the threatened Florida scrub‐jay, a species for which dispersal ability is unusually well‐characterized. The range‐wide population was intensively censused in the 1990s, and a metapopulation model defined population boundaries based on predicted dispersal‐mediated demographic connectivity. We subjected genotypes from more than 1000 individual jays screened at 20 microsatellite loci to two Bayesian clustering methods. We describe a consensus method for identifying common features across many replicated clustering runs. Ten genetically differentiated groups exist across the present‐day range of the Florida scrub‐jay. These groups are largely consistent with the dispersal‐defined metapopulations, which assume very limited dispersal ability. Some genetic groups comprise more than one metapopulation, likely because these genetically similar metapopulations were sundered only recently by habitat alteration. The combined reconstructions of population structure based on genetics and dispersal‐mediated demographic connectivity provide a robust depiction of the current genetic and demographic organization of this species, reflecting past and present levels of dispersal among occupied habitat patches. The differentiation of populations into 10 genetic groups adds urgency to management efforts aimed at preserving what remains of genetic variation in this dwindling species, by maintaining viable populations of all genetically differentiated and geographically isolated populations.

ACORN HARVESTING BY FLORIDA SCRUB JAYS

We documented numbers of acorns eaten, cached, and retrieved by Florida Scrub Jays (Aphelocoma coerulescens coerulescens), through one full annual cycle and part of another, in an oak scrub habitat characterized by abundant and reliable annual acorn crops. Jays consumed acorns during all months, with highest consumption from September through February and lowest in June and July. From August through December, most acorns consumed by jays were picked directly from shrubs; during the remaining 7 mo, acorns were recovered from ground stores. Acorn caching occurred throughout the fall, peaking in September and October. Data pooled across sex and age classes suggest that individual jays, on average, each cached between 6500 and 8000 acorns during fall of 1974. Only about one-third of those acorns were recovered later. Intact acorns recovered by Scrub Jays during fall usually were reburied, but by summer most recovered acorns were con- sumed. Acorn crops in the study area exhibit moderate annual variation but no crop failures. Acorns are available in substantial numbers every year, permitting Florida Scrub Jay territories to serve without fail as year-round warehouses of stored acorns. Those stores provide resources to carry group members through seasons of low arthropod availability, and perhaps facilitate delayed dispersal by juveniles. Use of a habitat characterized by relatively large and dependable annual acorn crops that are evenly dispersed, coupled with caching behavior, may contribute to the maintenance of permanent territoriality and co- operative breeding in this population.

Dominance in the Florida Scrub Jay

Studies of intraspecific dominance abound in the ornithological literature, but relatively few are based on the activities of free-living birds. The study of captive flocks, and even of wild groups attracted to feeding stations, may severely limit opportunities for discovering functions of dominance behavior in birds. Despite these limitations, several recent reports that in certain birds dominance is closely related to territoriality are convincing (Brown 1963, Dixon 1965, Wiley 1973, Smith 1976). More commonplace hypotheses relate dominance to differential allocation of limited food supplies (WynneEdwards 1962, Lack 1966: 284), though this relationship seems difficult to demonstrate in the field (despite Fretwell 1969). Florida Scrub Jays (Aphelocoma c. coerulescens) typically rear a single brood annually during a brief breeding season (Woolfenden 1973). Surviving offspring normally remain with their parents for at least one year during which they assist them in breeding (Woolfenden 1975). Eventually many of these helpers establish themselves as breeders either by replacing lost breeders of neighboring families or by founding new territories.

Multi-locus DNA fingerprinting supports genetic monogamy in Florida scrub-jays

Abstract Extensive behavioural and pedigree data on a colour-marked population of Florida scrub-jays (Aphelocoma coerulescens) suggested that this cooperatively breeding species is monogamous, with extremely rare exceptions in which males have two mates. We used multi-locus DNA fingerprinting to test these observations by determining genetic parentage. Despite restricted dispersal and high relatedness between behavioural parents and non-breeding members of the group, DNA fingerprints provided sufficient variability to determine parentage unambiguously in almost all cases. We found no evidence of extra-pair fertilisation of females or egg dumping, and confirmed a suspected case of polygyny in which a mother and daughter laid and incubated in the same nest. Our results confirm that detailed behavioural data allow accurate assignment of genetic parentage in this species. In Florida scrub-jays, large territory size may limit opportunities for cuckoldry, and persistent intense competition for limited breeding space may lead to low variance in the quality of established male breeders. These factors would reduce both the opportunity for, and benefits of engaging in extra-pair fertilisations. Delayed dispersal and cooperative breeding in this species have not evolved as avenues for direct reproduction by unpaired individuals.

Actuarial Senescence and Demographic Heterogeneity in the Florida Scrub Jay

Analysis of mortality from a 25-yr sample of 380 Florida Scrub Jays, Aphel- ocoma c. coerulescens, shows that actuarial senescence (increase in mortality with age) occurs. This refutes the notion that adult mortality is independent of age in birds, and has important implications for evolutionary dynamics. We point to two major factors that may act to mask underlying patterns of actuarial senescence: (1) Selection through time (de- mographic heterogeneity): because selection inevitably weeds out lower quality individuals first, overall mortality may appear to be constant or even decreasing, despite an increasing force of mortality acting on birds of higher quality. (2) Conflicting processes: one source of mortality may act to decrease mortality over time (e.g., group size effects), while another acts to increase it (e.g., degenerative senescence). Age-specific data, measures of intrinsic quality that are independent of mortality, and exposure of sources of heterogeneity and of conflicting processes allow us to demonstrate a clear pattern of actuarial senescence in an unmanipulated, natural population of long-lived birds. The slow rate of increase in mortality is consistent with the hypothesis that mortality increases more slowly with age in birds than in mammals.

Archiving primary data: solutions for long-term studies

The recent trend for journals to require open access to primary data included in publications has been embraced by many biologists, but has caused apprehension amongst researchers engaged in long-term ecological and evolutionary studies. A worldwide survey of 73 principal investigators (Pls) with long-term studies revealed positive attitudes towards sharing data with the agreement or involvement of the PI, and 93% of PIs have historically shared data. Only 8% were in favor of uncontrolled, open access to primary data while 63% expressed serious concern. We present here their viewpoint on an issue that can have non-trivial scientific consequences. We discuss potential costs of public data archiving and provide possible solutions to meet the needs of journals and researchers.