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The habitat of beach-nesting birds often overlaps with areas heavily used for human recreation. Human activity has been linked to negative behavioral and reproductive consequences for shorebirds; therefore, it is important for managers to understand how to best mitigate disturbance. In Florida, there is concern that human disturbance negatively affects the state-threatened population of Snowy Plovers (Charadrius nivosus). We measured response probabilities and flight initiation distances (FIDs) of Snowy Plovers at sites experiencing a range of human use. Snowy Plovers responded at longer distances to pedestrians and dogs than to competitor and predator species, except for incubating birds which responded at longer distances to predators. At all distances below 50 m, plovers had a response probability of > 0.2 for pedestrians. Dogs induced such strong reactions at close distances that plovers always displaced before they came within 20 m. Brood-rearing plovers were more sensitive to anthropogenic disturbance than plovers engaged in other behaviors. Plovers at sites with high disturbance generally had lower FIDs than birds at sites with less disturbance. Our findings illustrate the importance of accounting for differences in disturbance regimes among sites when setting buffer distances, and for protecting brood-rearing areas in addition to nesting habitat. Due to the severity of responses prompted by dogs, managers should strongly consider dog prohibitions at sites with breeding Snowy Plovers, as reasonable buffers may not be adequate. [ABSTRACT FROM AUTHOR]

The article focuses on the human disturbance caused to Charadrius nivosus also called Snowy Plovers during the breeding season in Northwest Florida. Topics discussed include the lack of basic data on disturbance rates and behavioral responses, unprotection of foraging and brood-rearing areas and sensitiveness of foraging adults to human beings. Other topics discussed include the need to evaluate the consequences of disturbance to foraging adults and mortality of chicks.

Abstract: The arrow shrimp, Tozeuma carolinense, is a highly abundant small crustacean inhabiting seagrass beds along the US southeastern and Gulf coast. These shrimp inhabit the tops of seagrass blades, feeding on epiphytic algae. Despite T. carolinense abundance, it is largely underrepresented in the diets of predatory fish, presumably due to its cryptic morphology and behavior. Here, we quantify the degree of crypsis of green and brown colormorphs of T. carolinense to the visual systems of two potential predators, dichromatic Cynoscion nebulosus and trichromatic Sciaenops ocellatus, using a visual chromatic contrast model. Contrast of shrimp colormorphs viewed against seagrass backgrounds was similar between predators but varied greatly for both colormorphs among the backgrounds. For both dichromatic and trichromatic predators, green morphs produced significantly less contrast than brown morphs on live seagrass, while brown morphs produced significantly less contrast than green morphs on dead seagrass. Each colormorph had at least one complimentary seagrass species against which it would be difficult for fish predators to discriminate. Model predictions were largely borne out in a survey of a natural population of T. carolinense in Tampa Bay, FL (USA), where shrimp were found only in monospecific patches of live Syringodium filiforme, and green morphs significantly outnumbered brown morphs. Although these shrimp do not rely solely on cryptic coloration for predator evasion, the ability of T. carolinense to match its background does minimize visual contrast and likely contributes to their lack of representation in the diets of predatory fish. [Copyright &y& Elsevier]

The authors discuss the results of their study on the influence of weather on the reproduction of Crested Caracara or Caracara cheriway in an agricultural landscape in south-central Florida. Higher rainfall frequency during late summer and early fall lowers productivity and increases nest failure. No significant relationship was found between rainfall proportion and vertebrate diet. It also revealed that Caracaras which build nests earlier in the breeding period had higher nest success and productivity, and had larger clutch sizes.

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Focuses on the ?Contaminant Exposure and Effects?Terrestrial Vertebrates? (CEE-TV) database which contains 4,336 records of ecotoxicological information for free-ranging amphibians, reptiles, birds, and mammals residing in Atlantic and Florida Gulf coast estuaries and their drainages.