Eudocimus albus: BirdLife International

Abstract As avian reproductive success is generally prey limited, identifying important prey types or sizes and understanding mechanisms governing prey availability are important objectives for avian conservation ecology. Irruptive White Ibis (Eudocimus albus) nesting at coastal colonies in the southern Everglades numbered over 100,000 nests in the 1930s. A century of drainage and altered hydrologic patterns reduced aquatic prey availability and eliminated large nesting events; nesting activity in recent decades has been typically less than 5% of historical peaks. Hydrologic restoration is expected to increase ibis nesting activity, but which prey types will support high nesting effort is less clear. In 2017 and 2018, we collected food boluses from White Ibis chicks at coastal colonies in Everglades National Park. We also monitored regional nesting activity from 1999 to 2018. In 2017, the region had 1,075 nests, typical of the past several decades; but in 2018, there were 30,420 nests, representing the highest recorded nesting activity in 87 yr. Prey composition varied between years; estuarine crabs dominated nestling boluses in 2017, while crayfish and fish were dominant prey in 2018. Crayfish, especially Procambarus alleni, were heavily exploited by ibis early in the 2018 breeding season, while fish were used more at the end. Crayfish abundances in wetlands near the colonies were higher prior to 2018, and more crayfish-producing short-hydroperiod wetlands remained available for ibis foraging in 2018. Our results support previous studies indicating that crayfish are important prey for breeding ibises and suggest that unprecedented, extensive flooding of seasonal wetlands promoted crayfish production and initiated the irruptive breeding in 2018. Our observations indicate that rehydration of the southern Everglades could restore ibis nesting activity at coastal colonies, but further investigations of hydrologic variation, crayfish production, and ibis foraging and nesting activity will be helpful to understand these dynamics and the importance of short-hydroperiod wetlands.

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FIRST NESTING RECORDS OF THE AMERICAN AVOCET (Recurvirostra americana) AND WHITE IBIS (Eudocimus albus) AT LAGUNA OJO DE LIEBRE, BCS, MÉXICO

CICIMAR Oceánides ◽

10.37543/oceanides.v29i1.131 ◽

2014 ◽

Vol 29 (1) ◽

pp. 19

Author(s):

V. Ayala -Pérez ◽

R. Carmona ◽

N. Arce ◽

J. Rivera

Keyword(s):

Eudocimus Albus ◽

American Avocet ◽

Recurvirostra Americana ◽

White Ibis

Primer registro de anidación de Avoceta americana (Recurvirostra americana) e Ibis blanco (Eudocimus albus) en Laguna Ojo de Liebre, BCS, México El humedal de Guerrero Negro es uno de los sitios de mayor relevancia para las aves acuáticas en México y es un sitio importante para su reproducción. Esta nota describe los primeros registros de anidación de Avoceta americana (Recurvirostra americana) e Ibis blanco (Eudocimus albus) en este humedal, incrementando con esto a 24 el número de especies cuya anidación se ha registrado en la zona.

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Fish Crow Predation on Eggs of the White Ibis at Battery Island, North Carolina

The Auk ◽

10.1093/auk/103.3.531 ◽

1986 ◽

Vol 103 (3) ◽

pp. 531-539 ◽

Cited By ~ 9

Author(s):

Mark A. Shields ◽

James F. Parnell

Keyword(s):

North Carolina ◽

Predation Rate ◽

Egg Predation ◽

Nest Attentiveness ◽

Eudocimus Albus ◽

White Ibis

Abstract We studied predation by Fish Crows (Corvus ossifragus) on eggs of the White Ibis (Eudocimus albus) during the 1983 and 1984 nesting seasons at Battery Island, southeastern North Carolina. Crow predation accounted for the loss of 32% (n = 223) of ibis eggs in 1983 and 44% (n = 538) in 1984. Crows usually took all eggs in a clutch. An estimated 6 pairs of Fish Crows nested on the island each year. We believe these individuals were responsible for most egg loss. The predation rate of ibis clutches was highest in plots nearest crow nests and lowest in two plots that contained observation blinds. Results of experiments using simulated ibis nests suggested that crows were wary of the blinds. Predation declined with nest age, apparently due to increased nest attentiveness by adult ibises during the last week of incubation. The overall predation rate in 1984 was significantly higher than in 1983. Greater nest densities and less synchronous breeding by ibises in 1984 may have contributed to the higher predation rate. Ibis productivity was estimated at 1.22-1.30 fledglings per pair in 1983 and 1.05-1.12 in 1984. This level of reproduction appeared sufficient for maintenance of the population. Thus, egg predation by Fish Crows during our study did not appear to be a serious threat to the productivity of this White Ibis population.

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Avian Response to Nutrient Enrichment in an Oligotrophic Wetland, the Florida Everglades

The Condor ◽

10.1093/condor/104.3.631 ◽

2002 ◽

Vol 104 (3) ◽

pp. 631-642

Author(s):

Gaea E. Crozier ◽

Dale E. Gawlik

Keyword(s):

Water Depth ◽

Florida Everglades ◽

Agelaius Phoeniceus ◽

Bird Abundance ◽

Ardea Herodias ◽

Eudocimus Albus ◽

Ardea Alba ◽

Geothlypis Trichas ◽

Mycteria Americana ◽

Quiscalus Major

Abstract We studied the effects of nutrient enrichment on the bird community in an oligotrophic wetland, the Florida Everglades. Among the non-wading birds surveyed in 1996 and 1997, Boat-tailed Grackles (Quiscalus major) and Common Moorhens (Gallinula chloropus) were consistently more abundant in enriched sites, whereas Common Yellowthroats (Geothlypis trichas) were consistently more abundant in unenriched sites. The abundance of Red-winged Blackbird (Agelaius phoeniceus) was not significantly different between enriched and unenriched sites. Among wading birds, Wood Storks (Mycteria americana) and Great Egrets (Ardea alba) were significantly more abundant in enriched than unenriched areas in a dry year, 1991. Great Egrets and all wading species combined were significantly more abundant in enriched than unenriched areas in the wet year, 1995. Great Blue Herons (Ardea herodias) and White Ibises (Eudocimus albus) did not differ in abundance between enriched and unenriched areas in the dry or wet year. A significant interaction between water depth and nutrient status in the wet year indicated that wading bird abundance increased with water depth only in nutrient-enriched areas presumably because the enriched areas had greater food availability than unenriched areas at the same water depth. Bird abundance appeared to increase in nutrient-enriched areas; however, this increase was accompanied by a shift in species composition typically found in the unenriched Everglades and was a fundamental change in the Everglades' distinctive structure. Respuestas de las Aves al Enriquecimiento con Nutrientes en un Humedal Oligotrófico, en los Pantanos de los Everglades en Florida Resumen. Estudiamos los efectos del enriquecimiento con nutrientes sobre la comunidad de aves en un humedal oligotrófico, los pantanos de los Everglades en Florida. Entre las aves no vadeadoras censadas en 1996 y 1997, Quiscalus major y Gallinula chloropus fueron consistentemente más abundantes en sitios enriquecidos, mientras que Geothlypis trichas fue consistentemente más abundante en sitios no enriquecidos. La abundancia de Agelaius phoeniceus no difirió significativamente entre los sitios enriquecidos y no enriquecidos. Entre las aves vadeadoras, Mycteria americana y Ardea alba fueron significativamente más abundantes en áreas enriquecidas que en las no enriquecidas durante 1991, un año seco. En 1995, un año húmedo, Ardea alba y todas las demás aves vadeadoras fueron significativamente más abundantes en áreas enriquecidas que en las no enriquecidas. Ardea herodias y Eudocimus albus no difirieron en abundancia entre áreas enriquecidas y no enriquecidas en el año húmedo ni en el año seco. En el año húmedo, encontramos una interacción significativa entre la profundidad del agua y el estado de los nutrientes, lo que indicó que la abundancia de aves vadeadoras aumentó sólo en las áreas enriquecidas con nutrientes, presumiblemente debido a que las áreas enriquecidas presentaron mayor disponibilidad de alimento que las áreas no enriquecidas de una profundidad de agua equivalente. La abundancia de aves pareció aumentar en las áreas enriquecidas con nutrientes; sin embargo, este incremento estuvo acompañado con un cambio en la composición de las especies encontradas normalmente en los pantanos de los Everglades de Florida que no han sido enriquecidos, y representó un cambio fundamental en la estructura característica de los Everglades.

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