Limpkin

Abstract: -I used a DNA-DNA hybridization method to generate more than 1,200 pairwise comparisons among species of the family Gruidae (cranes) and an outgroup Limpkin (Aramidae). A matrix of genetic distances included average delta T,, values for all cells, and reciprocals among cranes, based on 3-10 replicate experiments per cell. I chose delta T,, as the appropriate dissimilarity measure because virtually all homologous single-copy DNA sequences in crane genomes were sufficiently similar to form hybrid duplexes under standard experimental conditions. The normalized percent hybridization (NPH) values approached 100 for all crane species pairs. The delta T, data departed slightly from metricity as a result of experimental variation associated with the measurement of small genetic distances. The DNA data, analyzed with a best-fit tree approach and checked for internal consistency by jackknifing, support the traditional view that crowned cranes (Balearica) are the most ancient lineage of extant gruids. The enigmatic Siberian Crane (Grus leucogeranus) appears as the sister group of the remaining species, which fall into four closely related groups. Bugeranus and Anthropoides are sister groups. The three species of Australasian Grus (antigone, rubicunda, and vipio) form a clade, as do five predominantly Palearctic Grus (grus, monachus, nigricollis, japonensis, and americana). The Sandhill Crane (G. canadensis), while clearly a member of the gruine clade, is an old lineage without close relatives. Received 21 March 1989, accepted 18 May 1989. THE CLASSIFICATIONS of Peters (1934) and Wetmore (1934) established the traditional familylevel distinction of cranes (Gruidae) within the Order Gruiformes. This arrangement, though not universally accepted (Cracraft 1973), has persisted in most recent revisions (e.g. Wetmore 1960, Storer 1971, Sibley et al. 1988). Opinions regarding species affinities within the Gruidae have varied greatly. Following Peters (1934), most workers have accepted the existence of 14 extant species in four genera, though Walkinshaw's (1964) designation of a 15th species has gained many adherents. The crowned cranes (Balearica) are commonly placed in the Balearicinae, apart from the remaining species (Gruinae; Brodkorb 1967) based on their lack of sternal excavation and tracheal convolution. Balearicines, apparently the more ancient lineage, are abundantly represented by Tertiary fossil materials from western Eurasia (Brodkorb 1967). Gruine fossils appear in the Miocene of Europe, but are best represented in North American Pliocene deposits and by a scattering of Pleistocene remains worldwide (Johnsgard 1983). Cracraft (1973) inferred from these ma1 Current address: Museum Support Center, Smithsonian Institution, Washington, DC 20560 USA. terials that cranes diverged from a common ancestor with limpkins (Aramidae) in the late Paleocene. Archibald (1975, 1976) performed the first comprehensive analysis of cranes based on a coherent set of characters. His study of crane unison calls (stereotyped behavior patterns involved in pair-bonding) led him to identify clusters of similar species (Fig. 1). Archibald's work verified the distinctness of crowned cranes (Balearica) and suggested an unexpected relationship between Bugeranus carunculatus (Wattled Crane) and Grus leucogeranus (Siberian Crane). Archibald included leucogeranus as a member of Bugeranus, and recommended "Species Group" status for the remaining Grus and Anthropoides clusters. Wood (1979), like Archibald, found a high level of similarity between Wattled and Siberian cranes, which, aside from complicated multivariate resemblances, lack the exaggerated tracheal convolutions present in other gruines. Ingold et al. (1987) attempted to resolve crane relationships with allele-frequency analysis. Their species arrangement was a major departure from traditional views, although Balearica appears distinct from gruines. Their work involved small sample sizes, and only approxi603 The Auk 106: 603-618. October 1989 This content downloaded from 157.55.39.28 on Thu, 15 Dec 2016 04:53:04 UTC All use subject to http://about.jstor.org/terms 604 CAREY KRAlEwsKI [Auk, Vol. 106

Abstract: We identify two avian predators of the Neotropical apple snail, Pomaceaflagellata, and estimate the strength, direction and form of multivariate natural selection by these predators on size and colour of snail shells. Limpkins are tactile predators and act as agents of disruptive selection on snail size, selecting average-sized snails disproportionately more often than small or large snails (y = 0.39, SE = 0.08). In addition, we were able to identify variation in handling behaviours and snail size selection among individual limpkins. Individual limpkins showed preferences for snails of different sizes and punctured the snail shells opposite the aperture mainly when handling large snails. Snail kites are visual predators and seem to be agents of directional selection against lighter coloured snails (β= 0.66, SE = 0.33). The ecological interaction between the apple snail and its predators provides a powerful system to further explore the role of predation in determining evolutionary changes in snail behaviour, morphology and life history.

Abstract: The Limpkin (Aramus guarauna) is a medium-sized wading bird found in peninsular Florida and Central and South America, whose distribution is strongly tied to the presence of apple snails (genus Pomacea). Historically, Limpkins have been infrequently observed in the lower Apalachicola-Chattahoochee-Flint (ACF) watershed, including Lake Seminole, the most downstream reservoir in the system. In the past decade in Lake Seminole, a rapid increase in the nonnative P. maculata has been documented. In 2016, a Limpkin was observed in the lake, and we made efforts to document all subsequent Limpkin observations there. In the following year, we observed Limpkins (including several mating pairs) each month from February to July 2017. Limpkins were only observed in the Flint River section of the reservoir, the same area where the greatest abundance of P. maculata has been documented. We hypothesize the rapid increase of P. maculata is responsible for the recent regular Limpkin observations at the lake because observations of Limpkins prior to the recent expansion of P. maculata were rare and infrequent. Apple snails are likely to expand within the southeastern United States in the future, thereby creating additional suitable habitat for Limpkins and other specialist avian predators of apple snails.

Abstract: We document the first breeding record of Limpkin, Aramus guarauna (Linnaeus, 1766) (Gruiformes, Aramidae), for Louisiana, describe an additional unpublished breeding record from Georgia, as well as a possible record from Alabama, and associate these patterns with the concurrent establishment of the invasive Giant Apple Snail, Pomacea maculata Perry, 1810 (Caenogastropoda, Ampullariidae). We predict that an invasive prey species may facilitate range expansion by native predator species, which has ramifications for conservation and management.