Quiscalus Major Research Articles

Male rank, female breeding synchrony, and patterns of paternity in the boat-tailed grackle

Species in which males directly defend groups of breeding females often have extreme skew in observed male mating success. In only a few species, however, has a corresponding skew in fertilization success been confirmed. Furthermore, the ecological and social factors contributing to variation in fertilization success need investigation. This study examined competition for mates and paternity in the boat-tailed grackle (Quiscalus major). Observations at colonies of nesting females revealed that the topranking or alpha males performed more than 70% of the copulations. DNA fingerprinting indicated that alpha males sired less than 40% of nestlings. Nevertheless, analysis of band-sharing scores among nestlings from different nests suggested that alpha males sired more than three times as many offspring as any other individual male. Because few nestlings were sired by the nonalpha males that associated with colonies, females must have mated with other males while on trips away from colonies. Analysis of paternity within broods revealed that at least half of all females had their brood fertilized by more than one male. Alpha males’ success at fertilizing eggs did not vary with the number of simultaneously receptive females within a colony. Our results suggest that male and female behavior in female-defense polygyny results from complex coevolution of the sexes. Key words: boat-tailed grackle, DNA fingerprinting, female-defense polygyny, female synchrony, Quiscalus major. [Behav Ecol 10: 444‐451 (1999)]

Seed Color Avoidance by Captive Red-Winged Blackbirds and Boat-Tailed Grackles

Offensive visual stimuli represent a potentially important component of avian crop damage reduc- tion strategies. Color perception by diurnal birds is highly developed, but the responses of the red-winged blackbird (Agelaius phoeniceus) to different-colored food have never been investigated. Red-winged blackbirds and boat-tailed grackles (Quiscalus major) cause substantial damage to newly seeded rice in the southern United States, and the examination of color avoidance by these species should contribute to the development of nonlethal methods to reduce depredations. We used rice seed of various colors to conduct a series of feeding trials with captive blackbirds and grackles. Despite variation among individuals and groups of test birds, blue was the least preferred color overall. Differences among species and among background color might affect responses of birds to a given seed color, but, in general, we suggest that blue should be incorporated into strategies for discouraging unwanted feeding by granivorous birds. In particular, further development of visual deterrents should exploit the ability of blackbirds and other species to detect wavelengths in the near ultraviolet. JOURNAL OF WILDLIFE MANAGEMENT 63(3):1003-1008

Isomer-Specific Analysis and Toxic Evaluation of Polychlorinated Naphthalenes in Soil, Sediment, and Biota Collected near the Site of a Former Chlor-Alkali Plant

Concentrations and composition of polychlorinated naphthalene (PCN) congeners were determined in soil, sediments, blue crab, striped mullet, and boat-tailed grackle collected near a chlor-alkali plant to determine their congener profile, bioaccumulation properties, and toxic potential. Concentrations of total PCNs as high as 23 μg/g, dry wt, were found in sediments collected at the marsh contaminated by disposal of wastes from the chlor-alkali process. The spatial distribution of sediment−PCN concentrations was not related with those observed for polychlorinated biphenyls (PCBs). The PCN congener profile did not resemble those of any technical mixtures. Hepta- and octa-chloronaphthalenes were the most abundant congeners accounting for greater than 50% of the total PCN concentrations in soil and sediments. A characteristic profile of PCNs in samples collected at the chlor-alkali site suggests the formation of chloronaphthalene congeners during chlor-alkali process, as has been suggested for polychlorinated dibenzofurans (PCDFs). Concentrations of total PCNs in biota were 3−5 orders of magnitude less than in sediments. The profile of PCN congeners in biota was predominated by tetra- or penta-chloronaphthalenes, while hepta- and octa-chloronaphthalenes were not detected. Affinity of more chlorinated naphthalene congeners to sediment organic carbon and steric factors that affect membrane permeability have contributed to less bioavailability. The 2,3,7,8-TCDD equivalents (TEQs) estimated for PCNs in sediments and biota were greater than those reported for PCBs, PCDDs, or PCDFs. Our results suggest that the chlor-alkali process has been an important source of PCNs due to their formation in the process. The contribution of PCNs to dioxin-like toxicity in environmental media near the chlor-alkali process may overwhelm those due to PCBs, PCDDs, or PCDFs.

Anthraquinone protects rice seed from birds

Application of bird-repellent chemicals to seed prior to planting is one possible approach to reducing bird damage to rice. Anthraquinone is a promising seed treatment compound, and in this paper we describe a sequence of tests evaluating a formulated commercial anthraquinone product. In 1-cup cage tests, rice consumption by individual male red-winged blackbirds ( Agelaius phoeniceus) and female boat-tailed grackles ( Quiscalus major) was reduced 64–93% by 0.5 and 1.0% (g/g) anthraquinone treatments. Daily rice consumption by single male boat-tailed grackles tested in large enclosures was reduced from > 14 g in pretreatment to < 1 g by a 1.0% treatment. One of five test birds ate nothing during a 1 day post-treatment session. In a 7 day trial within a 0.2 ha flight pen, a group of four male grackles consumed 1.3% of anthraquinone-treated rice seed compared to 84.1% of sorghum, a nonpreferred alternate food. At two study sites in southwestern Louisiana, loss of rice sprouts in 2 ha plots sown with anthraquinone-treated seed was 0 and 12% compared to losses of 33% and 98% in nearby untreated plots. The formulation performed well at every stage of testing, and further development of anthraquinone products for bird-damage management is warranted.

Bioaccumulation and Toxic Potential of Extremely Hydrophobic Polychlorinated Biphenyl Congeners in Biota Collected at a Superfund Site Contaminated with Aroclor 1268

Aroclor 1268, a highly chlorinated technical PCB mixture composed of primarily hexa- through decachlorobiphenyls, was used to lubricate high voltage process equipment at a chlor-alkali facility in coastal southeastern Georgia. Disposal of process wastes has resulted in extensive contamination of environmental media at the nearby intertidal marsh. In this study, congener distribution, bioaccumulation properties, and toxic potential of superhydrophobic PCBs were examined in blue crab, fish, terrapin, and birds collected at this site. Lipid-normalized mean concentrations of total PCBs in blue crab, striped mullet, yellow tail, sea trout, diamondback terrapin, red-winged blackbird, boat-tailed grackle, mottled duck, and clapper rail were 197, 283, 203, 56, 14, 385, 76, 135, and 10 μg/g, respectively. Hepta-, octa-, and nonachlorobiphenyls col lectively accounted for 85−93% of the total PCB concentrations. The PCB congener profile in biota resembled that of Aroclor 1268, although the relative proportions of nona- and decachlorobiphenyls were less. Bioaccumulation of superhydrophobic congeners in biota, including terrapins and birds, was less than would be predicted from Kow, which supports the hypothesis that these compounds have restricted membrane permeability. Superhydrophobic PCB congeners were less efficiently transferred in the food web. The concentrations of non-ortho coplanar congeners in blue crab were 7−8 orders of magnitude less than the total PCB concentrations. Despite notable concentrations of total PCBs, the 2,3,7,8-TCDD toxic equivalents (TEQs) estimated for non- and mono-ortho-PCBs in biota were minimal. The toxic effects of higher chlorinated PCBs, including di-ortho-substituted PCBs, need further investigation.

Consumption of fipronil-treated rice seed does not affect captive blackbirds

Fipronil is an insecticide developed for use on rice seed and other crops. In a series of cage and pen trials, we evaluated the responses to dyed, fipronil-treated rice seed of three bird species likely to encounter it in the field. Individually caged red-winged blackbirds (Agelaius phoeniceus), brown-headed cowbirds (Molothrus ater), and boat-tailed grackles (Quiscalus major) displayed no evidence of adverse reaction to treated seed. Chemical analyses of hulls from treated seeds eaten by captive birds revealed that 10-20% of the fipronil originally present was removed during feeding. In group enclosures, male red-winged blackbirds ate as much fipronil-treated rice as they did dyed, untreated seed. In four-day tests within a 0.2-ha flight pen, 10-bird blackbird flocks removed 11.4% of fipronil-treated seed from a test plot compared to 12.5% of dyed, untreated seed removed from the alternate plot. When the alternate plot contained undyed rice, however, seed removal from the treated plot averaged 2.4% compared to 28.9% from the alternative plot, suggesting that the groups of test birds avoided treated seed based on its appearance. We conclude that 325 and 500 mg kg -1 fipronil applications alone do not affect avian feeding activity.

Feeding Deterrence of Anthraquinone, Anthracene, and Anthrone to Rice-Eating Birds

Safe, effective bird repellents are needed as seed treatments and for many other agricultural uses. Quinones are distributed widely in nature and many have predator defense and antiherbivory functions. One compound, 9,10-anthraquinone, was identified as a bird repellent in the 1940s, but is not registered for use in the United States. We evaluated it and 2 structurally related compounds, anthrone and anthracene, for repellency to rice-eating birds. In choice tests with individually caged red-winged blackbirds (Agelaius phoeniceus) anthraquinone and anthrone produced comparable reductions in consumption of treated rice at rates of 0.05, 0.10, and 0.25% (g/g). At 0.50%, however, only anthraquinone suppressed consumption of untreated rice as well as treated rice. Anthracene was least effective of the 3 compounds and was tested only at 0.50%. In 1-cup tests, consumption of anthraquinone-treated rice by individual blackbirds was suppressed at 0.10, 0.25, and 0.50%. Rice consumption by individually caged female boat-tailed grackles (Quiscalus major) exposed to the 0.50% treatment was similar to that of redwings at the 0.10% treatment. In choice tests of 3-bird groups in large flight enclosures, red-winged blackbirds discriminated strongly against 0.25% anthraqunione-treated rice. Observations of videotaped birds revealed no evidence of contact irritation or unpleasant taste; rather post-ingestive illness, as evidenced by one vomiting bird, suggests that anthraquinone repellency is due to learned behavior.

Mate choice and competition for mates in the boat-tailed grackle

Behavioural studies have implicated both female choice of mates and male competition for access to mates as proximate mechanisms of sexual selection. Few studies have examined the interactions between these mechanisms in a natural setting. In this study, I explored how dominance interactions between male boat-tailed grackles,Quiscalus majordetermine the mating success of males and how the behaviour of female boat-tailed grackles influences this process. Male grackles defended colonies of females and performed courtship displays to females that were building nests. These conspicuous displays incited dominance interactions between males, with the result that dominant males interrupted subordinate males’ attempts to copulate. Female grackles were receptive only to males that performed courtship displays, but their receptivity to males did not vary with male dominance rank or tail length. Females were more likely to be receptive in a colony than away from a colony, and females became receptive asynchronously during the breeding season. The timing and spacing of females' receptivity to males permitted dominance interactions between males to determine male mating success. By establishing the conditions for male competition, females indirectly chose high-ranking males. Recent studies have emphasized discrimination among potential mates as a behavioural mechanism for mate choice. The results reported here, however, demonstrate that other aspects of females' behaviour can produce mate choice, indirectly rather than directly.

Dominance, access to colonies, and queues for mating opportunities by male boat-tailed grackles

Species characterized by female-defense polygyny have extreme variance in male mating success. Many studies have considered alternative male strategies for access to females, but few have considered age-specific strategies. Male boat-tailed grackles (Quiscalus major) compete for access to colonies of females and form linear dominance hierarchies. I observed two groups of males that competed for females at seven colonies. Dominance rank was significantly correlated with mass, but not after controlling for age. In contrast, the correlation between dominance rank and age remained significant after controlling for mass. Older males dominated younger males and dominance relationships were very stable. Thus, dominance hierarchies represent queues for mating opportunities. A male's rank in the hierarchy determined how closely he approached a colony. Furthermore, males of all ranks prevented lower-ranked individuals from approaching the colonies. Dominance rank thus determined access to nesting females. One top-ranking male's loss of mass over the course of the breeding season presumably reflected the energetic cost of defending females, but he maintained his position in the hierarchy despite the small loss of mass. One alpha male held a colony for at least 4 years, and the ages of males from two queues indicated that males wait 6 or more years before becoming an alpha male. Therefore, most males die before acquiring a colony of females. Spatial structure such as that documented here could obscure recognition of queues and explain why they have not been documented in more species.

Assessing the Hazard to Granivorous Birds Feeding on Chemically Treated Seeds

Current methods for evaluating hazards to seed-eating birds are based on estimated exposure per unit area and assume that birds ingest all of the chemical on a treated seed. In an earlier study, however, it was determined that red-winged blackbirds removed only about 15% of an insecticidal treatment applied to individual rice seeds. Here, we extend those -ndings by examining the seed-handling behavior of four granivorous bird species exposed to millet, rice, sunNower and sorghum treated with imidacloprid. Mourning doves (Zenaida macroura L.) swallowed the seed whole. House -nches (Carpodacus mexicanus Mue ller), red-winged blackbirds (Agelaius phoeniceus L.) and boat-tailed grackles (Quiscalus major Vieillot) discarded the seed hulls, however, and removed only 15E40% of the initial chemical treatment. Residues on seed hulls decreased as handling time increased. SunNowers had the lowest residues because birds repeatedly handled the hull to remove bits of the oily kernel. These results suggest that avian hazard assessment methods should incorporate species-typical seed-handling behavior to assess more accurately birdsI exposure to chemicals on di†erent types of seed.

Mint plant derivatives as blackbird feeding deterrents

Naturally occurring plant constituents are potentially useful as avian feeding deterrents. In a series of cage trials, pulegone, a compound found in various species of mint, suppressed consumption of rice seed by red-winged blackbirds ( Agelaius phoeniceus) more effectively than methyl anthranilate. Furthermore, pennyroyal oil, from which pulegone is obtained, was nearly as effective as pulegone itself. Brown-headed cowbirds ( Molothrus ater) were more sensitive to pulegone than were redwings, but female boat-tailed grackles ( Quiscalus major) were less sensitive. Because pulegone produces both sensory irritation and post-ingestive distress, it has potential for seed treatment and other bird deterrent applications.

Boat-tailed Grackle (Quiscalus major)

Boat-tailed Grackle (Quiscalus major)

A comparison of passerine foraging habits in two tidal marshes of different salinity

Foraging habits of dominant passerine species of the Savannah River National Wildlife Refuge, SC, were compared in freshwater and brackish marshes. Temporal or spatial partitioning was evaluated using discriminant function analysis of the distribution among feeding time, foraging height, marsh elevation zone, and plant-type habitat variables by red-winged blackbirds (Agelaius phoeniceus), boat-tailed grackles (Quiscalus major), long-billed marsh wrens (Cistothorus palustris), and common yellowthroats (Geothlypis trichas). Marsh elevation zone and plant type often occurred together as significant variables due to the zonal distribution of marsh plants, especially in the freshwater marsh. Likewise, foraging height often occurred as a significant variable along with plant type due to the dependence of foraging height on plant type and location of preferred food on a plant species. Partitioning of habitat variables was observed more frequently in the brackish marsh when compared with the freshwater marsh. Lower diversity of plant species and food items, combined with a greater zonation of plant communities in the brackish marsh, is proposed to account for the differences observed between the two marshes. Differences in community structure and scale of partitioning between the freshwater and brackish marsh also suggest that the brackish marsh may be more advantageous to generalist species contrasted with specialists. We postulate that conversion of freshwater marshes to brackish marshes, as might be caused by hydrologic alterations, ground-water withdrawal, or global sea-level rise, may create conditions that would favor generalist species.

Avian exposure to organophosphorus and carbamate pesticides on a coastal South Carolina golf course

AbstractA field study was conducted to examine avian exposure to organophosphorus (OP) and carbamate (CA) pesticides applied to turf on a coastal South Carolina golf course. The number, distribution, and activity of birds on turfgrass were monitored from May 25 to August 27, 1993. Over 1,600 birds representing 23 species were counted on turfgrass during designated monitoring sessions and incidental observations. Most birds were observed during morning hours, on fairways, and on the back nine holes of the course. Foraging was the predominant behavior observed. Blood samples and footwashes were collected from red‐winged blackbirds (Agelaius phoeniceus), common grackles (Quiscalus quiscula), and boat‐tailed grackles (Quiscalus major) for measurement of plasma cholinesterase (ChE) activity and chemical residues, respectively. Reactivation of plasma ChE in 22 blood samples suggested CA exposure, but no overt signs of anti‐ChE poisoning were observed in birds sampled. However, an incapacitated laughing gull discovered after an application of the CA bendiocarb (3.36 kg/ha) exhibited 87% depression of plasma ChE and displayed symptoms consistent with OP/CA intoxication. Pesticide exposure was confirmed by recovery of 50.33 μg bendiocarb in the footwash. Mole crickets (Scapteriscus spp.) that surfaced following the same chemical application contained bendiocarb residues and may have been ingested by foraging birds. Results of this study suggest a potential for avian exposure to OP and CA pesticides on the golf course, but few actual exposures and acute effects were observed.

Are female boat-tailed grackle colonies neutral assemblages?

Are female boat-tailed grackle colonies neutral assemblages?

Are female boat-tailed grackle colonies neutral assemblages?

Female boat-tailed grackles (Quiscalus major) nest in colonies, and apparently settle independently of male activities. Associations between colony females may be mutually beneficial (cooperative hypothesis) or females may be penalized by associating (competitive hypothesis). Contrary to predictions based on either cooperative or competitive behavior, (1) reproductive success was not related to colony size nor to internest distance; (2) intracolony nesting synchronies were the same as those of the whole population, and within colonies, there was no relationship between the timing and spacing of nearest-neighbor nests; and (3) already established females were only occasionally aggressive toward females attempting to settle near them, and their aggressive response was independent of their stage of nesting. The results suggest that females act independently of each other and do not affect each other's fitness (neutral female hypothesis). Colonies may be neutral aggregations in sites secure from ground predators. Although females benefit by co-occupying predator-free sites, advantages and disadvantages of colomality do not appear to be related to intrasexual association.

Effect of Selection for Successful Reproduction on Hatching Synchrony and Asynchrony

-Hypotheses regarding the evolution of asynchronous hatching in birds are evaluated with respect to the Murray-Nolan clutch-size equation, which distinguishes between the number of broods successfully reared per female during a breeding season (2:1 Pi) and within-brood survivorship (which affects Z. Xx). Asynchronous hatching is best interpreted as an adaptation that reduces the probability of whole-brood loss to predation, inclement weather, or other cause of whole-brood mortality (i.e. it increases a female's probability of rearing at least one young to nest-leaving from a clutch, and increases 1 P). This hypothesis constitutes a different form of the hypotheses of Tyrvainen, Hussell, and Clark and Wilson. The equations of Clark and Wilson and of Hussell erred in assuming a stepped function of the probability of daily survivorship (dj) during the nesting cycle. Instead, I assume a smooth curve and argue that if d, < 1 and if sn = II d,, then asynchronous hatching results in increasing s, and 2;1 Pi of the clutch-size equation. Alternative hypotheses explaining the evolution of asynchronous hatching seem better interpreted as explanations for increasing within-brood success, increasing the number of young to nest-leaving (kn) of successful broods, and increasing w Ax, of the clutch-size equation, or as unselected consequences of selection for reducing whole-brood loss. Received 26 July 1993, accepted 11 January 1994. BIRDS LAY no more than one egg per day, and incubation may begin at any time during the laying sequence. If incubation begins before the last egg is laid, hatching may be asynchronous. Several hypotheses have been proposed to explain the evolution of asynchronous hatching. They include the notions that asynchronous hatching may: (1) result in rapid brood reduction when feeding conditions are poor (Lack 1947, 1954, Ricklefs 1965, Pijanowski 1992); (2) reduce the probability of whole brood loss (Tyrvainen 1969, Hussell 1972, Clark and Wilson 1981); (3) reduce the peak feeding load on adults (Hussell 1972, 1985a); (4) result from laying insurance eggs after incubation has begun (Dorward 1962, Nisbet and Cohen 1975, Stinson 1979); (5) shorten the time during which a clutch is vulnerable to brood parasitism (Wiley and Wiley 1980, Lombardo et al. 1989); (6) reduce sibling rivalry (Hahn 1981); (7) reduce the time that adults are exposed to predation (Magrath 1988); (8) result in greater paternal contribution to the brood (Slagsvold and Lifjeld 1989); or (9) reduce the loss of early laid eggs to inviability (Veiga 1992). Mead and Morton (1985), however, suggested that asynchronous hatching is not adaptive at all but an incidental consequence of the hormonal mechanism controlling the transition from egg laying to incubation. From my clutch-size theory (Murray 1979, 1991a), I infer that asynchronous hatching increases the probability of successful reproduction of parents by reducing the probability of whole-brood loss. Thus, the clutch-size theory lends support to the hypothesis of Tyrvainen (1969), Hussell (1972), and Clark and Wilson (1981), although my argument is different from theirs. Empirical data gleaned from the literature, however, indicate that hatching is more synchronous than expected from the theory (Clark and Wilson 1981, Slagsvold 1986, Magrath 1990). Furthermore, studies on the Boat-tailed Grackle (Quiscalus major; Bancroft 1985), Least Flycatcher (Empidonax minimus; Briskie and Sealy 1989), and Yellow Warbler (Dendroica petechia; Hebert and Sealy 1993), specifically undertaken to test the hypothesis, confirm that hatching is more synchronous than expected from the formulations of Clark and Wilson (1981) and Hussell (1985a, b). Thus, the nest-failure hypothesis seems to have little empirical support. In this paper I examine the nest-failure hypothesis and some other hypotheses on asynchronous hatching in light of my clutch-size theory. THE HUSSELL EQUATION Tyrvainen (1969), Hussell (1972), and Clark and Wilson (1981) proposed that asynchronous hatching evolved as a means of reducing the

Nesting Associations of Least Bitterns and Boat-Tailed Grackles

Nesting Associations of Least Bitterns and Boat-Tailed Grackles

Dominance and mating success in male boat-tailed grackles

A study of boat-tailed grackles, Quiscalus major, shows how variation in male mating success is related to dominance rank and to competition for concentrations of breeding females. Males were organized in an absolute dominance hierarchy that was stable over a 4-year period. Position in the hierarchy was positively correlated with age, but not with size. Before the spring arrival of females, individual males dispalayed at many potential colony sites, but during the breeding period concentrated at those sites that had been colonized by females. Male attendance and display rates were correlated with numbers of fertilizable females. A mean of 4·7 males was present for each such female. A male's position in the dominance hierarchy determined its access to females. Most matings occurred at the nest, and as nests were close together and as nesting was asynchronous, first-ranking males were able to monopolize receptive females: 80% of copulations were by these males. During the first-ranking male's absence, other highranking males landed at nests, and were able to mate. Mid-ranking males remained at the periphery of colonies, and moved between different locations, apparently in response to the presence of fertilizable females. Low-ranking males rarely associated with colonies, but gathered in separate areas, where they attempted unsuccessfully to copulate with foraging females.

Alternative Foods of a Diet Specialist, the Snail Kite

Although Snail Kites (Rostrhamus sociabilis) in Florida and Venezuela fed mostly on Pomacea snails, I documented three alternative foods. In Florida, kites fed on five species of turtles, but especially on Sternotherus odoratus and Kinosternon bauri. During the height of a drought, one kite in Florida fed on a aquatic snail (Viviparus georgianus) for 5 weeks.- In Venezuela, freshwater crabs (Dilocarcinus dentatus) made up on average 10% of the Snail Kite's diet, but more than 25% during September and October. Kites consumed alternative foods with techniques that resemble snail-eating behavior, such as entering a turtle's body cavity by piercing the only leg shaped like a snail operculum. Handling times for turtles (76 min) and crabs (5.4 min) were much longer than for Pomacea snails (1.5 min). Viviparus snails required approximately one-third less handling time but contained one-fifth less body mass than Pomacea snails. Handling time (30 s) for V. georgianus did not differ between the Snail Kite and the Boat-tailed Grackle (Quiscalus major), a diet generalist. These findings are related to the factors that reinforce diet specialization and the ecological conditions that promote diet diversification in specialists. Like Pomacea snails, alternative foods have shells or carapaces and move relatively slowly. Alternative foods are probably less profitable than Pomacea snails, except for large crabs. Although crabs were regularly eaten by kites in Venezuela, turtles and Viviparus snails were eaten in Florida only during times of food scarcity. Received 9 June 1989, accepted 6 November 1989. DEPENDENCE on a single prey type is unusual among vertebrates, but may be more common in invertebrates (Bristow 1988). A notable ex- ception, the Snail Kite (Rostrhamus sociabilis), feeds almost exclusively on one genus of fresh- water snails (Pomacea). In Florida the kite eats only Pomacea paludosa (Howell 1932, Snyder and Snyder 1969, Sykes 1987), while in Central and South America several Pomacea species are eaten (Haverschmidt 1962, 1970; Beissinger 1983; Snyder and Kale 1983; Bourne 1985). Alterna- tive foods are taken on rare occasions. These include turtles (Sykes and Kale 1974, Woodin and Woodin 1981, Takekawa and Beissinger 1989) and a mammal (Sykes and Kale 1974). Other less carefully documented observations of nonsnail foods include a small yellowish serpent (Slud 1980), a ring-necked snake (Dia- dophis punctatus), and a dead American Coot (Fu- lica americana) (Sykes 1987). In Venezuela and Colombia, kites fed on freshwater crabs and