scholarly journals Dramatic reduction in predation on marine turtle nests through improved predator monitoring and management

Oryx ◽  
2005 ◽  
Vol 39 (3) ◽  
pp. 318-326 ◽  
Author(s):  
Richard M. Engeman ◽  
R. Erik Martin ◽  
Henry T. Smith ◽  
John Woolard ◽  
Carrie K. Crady ◽  
...  
Keyword(s):  
Nest Predation ◽  
Management Strategies ◽  
Predation Rate ◽  
Marine Turtle ◽  
Conservation Implications ◽  
Turtle Conservation ◽  
Predator Management ◽  
Successful Design ◽  
Patterns Of Behavior ◽  
Tracking Plot

We describe improvements to monitoring/indexing methodology for predators of marine turtle nests on the east coast of Florida, and the resulting marine turtle conservation implications from integrating the methodology into predator management. A strip transect from dune line to the shore improved an already successful design for monitoring raccoons, and was also sensitive for armadillos. The data were integrated into predator management operations to effectively and efficiently remove the species responsible for turtle nest predation. Tracking plot data also served to validate predator patterns of behavior relative to turtle nesting and improve prospects for preventive predator management strategies. Perhaps the most important finding is that predation at a beach historically suffering nearly complete losses (95%) of marine turtle nests had nest predation reduced to nominal levels (9.4%). For 2002 this predation level represents an estimated 69,000 additional hatchling turtles produced over historical predation rates, and 16,700 additional hatchlings over the previous lowest predation rate.

scholarly journals An ideal combination for marine turtle conservation: exceptional nesting season, with low nest predation resulting from effective low-cost predator management

Oryx ◽  
2011 ◽  
Vol 46 (2) ◽  
pp. 229-235 ◽  
Author(s):  
Richard Engeman ◽  
R. Erik Martin ◽  
John Woolard ◽  
Margo Stahl ◽  
Charles Pelizza ◽  
...  
Keyword(s):  
Nest Predation ◽  
Low Cost ◽  
Loggerhead Turtle ◽  
Chelonia Mydas ◽  
Economic Benefits ◽  
Marine Turtle ◽  
Management Approach ◽  
Predator Control ◽  
Marine Turtles ◽  
Predator Management

AbstractWe examined impacts from effective predator management on nesting success of marine turtles in an exceptional nesting year at Hobe Sound National Wildlife Refuge, Florida, USA, a beach with a high density of nesting marine turtles that has a history of severe nest predation. Historically up to 95% of nests were predated, primarily by raccoons Procyon lotor and, more recently, armadillos Dasypus novemcinctus. Predator control was identified as the most important conservation tool for marine turtle reproduction. Predator management by refuge staff as ancillary duties typically only held predation levels to c. 50%. However, when experts in predator control were employed predation was substantially reduced. An extraordinary opportunity to evaluate the biological and economic benefits of this management approach occurred in 2008, a year with exceptionally heavy nesting. Loggerhead turtle Caretta caretta nesting resurged, green Chelonia mydas and leatherback Dermochelys coriacea turtles nested in record numbers, producing twice or more than their median number of nests, and the first Kemp’s ridley Lepidochelys kempii nest was observed. Overall predation was 14.7%, resulting in an estimated > 128,000 additional hatchlings emerging compared to estimates had no predator management been in place and historical predation rates occurred, and > 56,000 hatchlings more than expected had predator management been conducted as ancillary duties rather than by experts. The USD 12,000 investment for expert predator management equated to only USD 0.09 spent for each additional hatchling produced compared to the scenario of no predator control and only USD 0.21 compared to the scenario of predator control as ancillary duties.

scholarly journals Improving marine turtle conservation in Myanmar

Oryx ◽  
2019 ◽  
Vol 53 (3) ◽  
pp. 409-409
Author(s):  
Robert Howard ◽  
Ko Myint ◽  
Phone Maw ◽  
Phone Zaw ◽  
Manjula Tiwari
Keyword(s):  
Marine Turtle ◽  
Turtle Conservation

scholarly journals Factors Influencing Predation on Ovenbird (Seiurus Aurocapilla) Nests in Northern Hardwoods: Interactions Across Spatial Scales

The Auk ◽  
2006 ◽  
Vol 123 (1) ◽  
pp. 82-96
Author(s):  
Brady J. Mattsson ◽  
Gerald J. Niemi
Keyword(s):  
Nest Predation ◽  
Spatial Scales ◽  
Agricultural Practices ◽  
Predation Rate ◽  
Mean Values ◽  
Core Habitat ◽  
Litter Depth ◽  
Seiurus Aurocapilla ◽  
Forest Songbirds ◽  
Main Effects

Abstract Microsite, patch, and landscape conditions may interact to influence nest predation. In northern Minnesota, silvicultural and agricultural practices may be involved in recent increases in nest predators and regional declines in several ground-nesting songbirds. To examine this problem, we evaluated 17 hierarchical models of predation on Ovenbird (Seiurus aurocapilla) nests that included microsite variables, distances to edges, and amount of core forest within a 2-km radius surrounding six study plots. During 2000 and 2001, 157 Ovenbird nests were monitored to estimate nest predation rates. A model that included the main effects of litter depth and core forest area and an interaction term between the two best described variation in predation on Ovenbird nests (AICc weight = 0.83). The nest predation rate from this model was 0.51 ± 0.01 (mean ± SE), assuming mean values of litter depth and amount of core forest. Shallow litter was associated with higher nest predation in three plots surrounded by less core habitat (40–60 ha), whereas there was no relationship in three plots surrounded by more core area (100–150 ha). Management that promotes deep leaf litter and the maintenance of large, intact forest tracts will likely benefit Ovenbirds and other forest songbirds. Factores que Influencian la Depredación de Nidos de Seiurus aurocapilla en los Bosques del Norte: Interacciones a través de las Escalas Espaciales

scholarly journals Defending against disparate marine turtle nest predators: nesting success benefits from eradicating invasive feral swine and caging nests from raccoons

Oryx ◽  
2014 ◽  
Vol 50 (2) ◽  
pp. 289-295 ◽  
Author(s):  
Richard M. Engeman ◽  
David Addison ◽  
J.C. Griffin
Keyword(s):  
Nest Predation ◽  
Sus Scrofa ◽  
Nesting Success ◽  
Marine Turtle ◽  
Financial Cost ◽  
Feral Swine ◽  
Predator Species ◽  
Marine Turtles ◽  
Nest Protection ◽  
Nesting Season

AbstractNest predation can threaten marine turtle nesting success, and having to address dissimilar predator species complicates nest protection efforts. On Florida's Keewaydin Island predation by raccoons Procyon lotor and invasive feral swine Sus scrofa are disparate, significant threats to marine turtle nests. Using 6 years of nesting data (mostly for loggerhead marine turtles Caretta caretta) we examined the impacts of swine predation on nests and the benefits of swine eradication, caging nests to protect them from raccoon predation, and the effects of nest caging on swine predation. Nest predation by swine began in mid nesting season 2007, after which swine quickly annihilated all remaining marine turtle nests. During 2005–2010 raccoon predation rates for caged nests (0.7–20.4%) were significantly lower than for uncaged nests (5.6–68.8%) in every year except 2009, when little raccoon predation occurred. The proportions of eggs lost from raccoon-predated nests did not differ between caged and uncaged nests. Caging did not prevent destruction by swine but median survival time for caged nests was 11.5 days longer than for uncaged nests, indicating that caged eggs in nests have a greater chance of hatching before being predated by swine. The financial cost of the eradication of swine greatly outweighed the value of hatchlings lost to swine predation in 2007.

scholarly journals Nestling begging calls increase predation risk by corvids

2019 ◽  
Vol 69 (2) ◽  
pp. 137-155
Author(s):  
Magne Husby
Keyword(s):  
Nest Predation ◽  
Predation Rate ◽  
Artificial Nest ◽  
Auditory Cues ◽  
Artificial Nests ◽  
Breeding Failure ◽  
Nestling Begging ◽  
Real Costs ◽  
Insight Into ◽  
Nest Predators

Abstract Despite nest predation being the most common cause of breeding failure in open-nesting birds, we have little insight into the cues used by nest predators when they search for nests. So far we have assumed that nest-predating birds are visually oriented while mammal predators to a large extent use scent and auditory cues like nestling begging calls. To evaluate how important nestling begging calls are for corvid nest predators searching for nests, I used artificial nests, which made it possible to find the real costs of the begging without mitigation by parental and nestling behavior. I used paired artificial nests, one with and one without nestling begging call playback. Within 10 days, 62.9% of the nests were predated. The analyses showed that nests with begging calls suffered a significantly higher predation rate than nests without begging calls, especially when the nests were placed close to corvid nests. Moreover, nests with begging calls were predated significantly earlier than nests without begging calls. In artificial nest pairs with both nests predated but on different days, nests with begging calls were predated first. In nest pairs with only one predated nest, nests with begging calls were predated most often. This experiment shows that nestling begging calls imply a cost in terms of increased and earlier nest predation, and that corvids use nestling begging calls as a cue to find and depredate bird nests, challenging earlier expectations.

scholarly journals Diel timing of nest predation changes across season in a subtropical shorebird

2021 ◽  
Author(s):  
Martin Sládeček ◽  
Kateřina Brynychová ◽  
Esmat Elhassan ◽  
Miroslav Salek ◽  
Veronika Janatová ◽  
...  
Keyword(s):  
Incubation Period ◽  
Activity Pattern ◽  
Nest Predation ◽  
Predation Rate ◽  
Limited Information ◽  
Nest Failure ◽  
Common Cause ◽  
Ground Temperatures ◽  
Geographical Regions ◽  
Ground Nesting

Predation is the most common cause of nest failure in birds. While nest predation is relatively well studied in general, our knowledge is unevenly distributed across globe and taxa, with for example limited information on shorebirds breeding in sub-tropics. Importantly, we know fairly little about the timing of predation within a day and season. Here, we followed 499 nests of red-wattled lapwings (Vanellus indicus), a ground-nesting shorebird, to estimate a nest predation rate, and continuously monitored 231 of these nests for a sum of 2951 days to reveal how timing of predation changes over the day and season in a sub-tropical desert. We found that 324 nests hatched, 77 nests were predated, 38 failed for other reasons and 60 had unknown fate. Daily predation rate was 0.97% (95%CrI: 0.77% – 1.2%), which for a 30-day long incubation period translates into ~25% chance of nest being predated. Such predation rate is low compared to most other species. Predation events were distributed evenly across day and night, with a tendency for increased predation around sunrise. Predation rate and events were distributed evenly also across the season, although night predation was more common later in the season, perhaps because predators reduce their activity during daylight to avoid extreme heat. Indeed, nests were never predated upon when mid-day ground temperatures exceeded 45°C. Whether the activity pattern of predators indeed changes across the breeding season and whether the described predation patterns hold for other populations, species and geographical regions awaits future investigations.

scholarly journals Widespread anthropogenic translocation of the African Clawed Frog across its native range is revealed by its co-introduced monogenean parasite in a co-phylogeographic approach

2021 ◽  
Author(s):  
Anneke Lincoln Schoeman ◽  
Louis Heyns du Preez ◽  
Nikol Kmentová ◽  
Maarten P M Vanhove
Keyword(s):  
Management Strategies ◽  
Invasion Biology ◽  
Holistic Approach ◽  
Life Cycles ◽  
Invasion Success ◽  
Native Range ◽  
Invasive Range ◽  
Conservation Implications ◽  
Host Lineage ◽  
Live Bait

1. The management of biological invasions relies upon the development of methods to trace their origin and expansion. Co-introduced parasites, especially monogenean flatworms, are ideal tags for the movement of their invasive hosts due to their short generations, direct life cycles and host specificity. However, they are yet to be applied to trace the intraspecific movement of species in their native ranges. 2. As proof of this concept, we conducted a co-phylogeographic analysis based upon two mitochondrial markers of a globally distributed frog Xenopus laevis and its monogenean flatworm parasite Protopolystoma xenopodis in both its native range in southern Africa and its invasive range in Europe. 3. Translocation of lineages was largely masked in the frog's phylogeography. However, incongruent links between host and parasite phylogeography indicated host switches from one host lineage to the other after these were brought into contact due to human-mediated translocation in the native range. Thus, past translocation of host lineages is revealed by the invasion success of its co-introduced parasite lineage. 4. This study demonstrates the concept that parasite data can serve as an independent line of evidence in invasion biology, also on the intraspecific level, shedding light on previously undetected invasion dynamics. Based upon the distribution of these invasive parasite lineages, we infer that the widespread translocation of hosts is mainly facilitated by the frog's use as live bait by the local angling communities and not via official export routes. 5. Data from co-introduced, host-specific parasites can add value to investigations in invasion biology and conservation. A better understanding of the translocation history and resulting genetic mixing of animals in their native ranges prior to introduction into new environments can inform management strategies in the invasive range. Knowledge of the intraspecific movement of different lineages of animals in their native ranges also has conservation implications, since contact between divergent lineages of hosts and parasites can facilitate host switches and altered parasite dynamics in both native and invasive populations. Therefore, we recommend the inclusion of parasite data as a more holistic approach to the invasion ecology of animals on the intraspecific level.

scholarly journals Predation on Real and Artificial Nests in Shrubsteppe Landscapes Fragmented by Agriculture

The Condor ◽  
2002 ◽  
Vol 104 (3) ◽  
pp. 496-506 ◽  
Author(s):  
W. Matthew Vander Haegen ◽  
Michael A. Schroeder ◽  
Richard M. DeGraaf
Keyword(s):  
Nest Predation ◽  
Survival Rates ◽  
Predation Rate ◽  
Future Research ◽  
Fragmented Landscape ◽  
Corvus Corax ◽  
Artificial Nests ◽  
Fragmented Landscapes ◽  
Eastern Washington ◽  
Predation Rates

Abstract Clearing of shrubsteppe communities for agriculture has created a highly fragmented landscape in eastern Washington, a condition that has been shown to adversely affect nesting success of birds in some forest and grassland communities. We used artificial nests monitored by cameras to examine relative effects of fragmentation, distance to edge, and vegetation cover on nest predation rates and to identify predators of shrubsteppe-nesting passerines and grouse. Predation rate for artificial nests was 26% (n = 118). Fragmentation had a strong influence on predation rates for artificial nests, with nests in fragmented landscapes about 9 times more likely to be depredated as those in continuous landscapes. Daily survival rate (± SE) for 207 real nests of 4 passerine species also was greater in continuous (0.978 ± 0.004) than in fragmented (0.962 ± 0.006) landscapes, although pattern of predation between real and artificial nests was not consistent among sites. Artificial nests were depredated by Common Ravens (Corvus corax), Black-billed Magpies (Pica hudsonia), Sage Thrashers (Oreoscoptes montanus), least chipmunks (Tamias minimus), and mice. Most nests in fragments were depredated by corvids (58%), whereas only Sage Thrashers and small mammals depredated nests in continuous landscapes. Increased predation by corvids and lower nest success in fragmented landscapes may have played a part in recent declines of some shrubsteppe birds. Future research should measure annual reproductive success of individual females and survival rates of juveniles and adults. Depredación de Nidos Naturales y Artificiales en Paisajes de Estepa Arbustiva Fragmentados por Agricultura Resumen. El reemplazo de estepa arbustiva por campos de cultivo ha creado un paisaje altamente fragmentado en el este de Washington, afectando adversamente el éxito de nidificación de aves en algunas comunidades de bosque y pastizal. Usamos nidos artificiales monitoreados por cámaras para examinar los efectos relativos de la fragmentación, la distancia al borde y la cobertura de la vegetación sobre las tasas de depredación de nidos, y para identificar los depredadores de paserinos y gallinas silvestres (Phasianidae) que nidifican en la estepa arbustiva. La tasa de depredación de los nidos artificiales fue del 26% (n = 118). La fragmentación tuvo una fuerte influencia en las tasas de depredación de nidos artificiales, ya que los nidos en paisajes fragmentados tuvieron una probabilidad de ser depredados 9 veces mayor que aquellos en paisajes continuos. La tasa de supervivencia diaria (± EE) de 207 nidos naturales pertenecientes a 4 especies de paserinos también fue mayor en paisajes continuos (0.978 ± 0.004) que fragmentados (0.962 ± 0.006), aunque el patrón de depredación entre nidos naturales y artificiales no fue consistente entre sitios. Los nidos artificiales fueron depredados por Corvus corax, Pica hudsonia, Oreoscoptes montanus, Tamias minimus y ratones. La mayoría de los nidos en fragmentos fueron depredados por C. corax (58%), mientras que sólo O. montanus y pequeños mamíferos depredaron nidos en paisajes continuos. Un incremento en la depredación por parte de C. corax y un menor éxito de los nidos en paisajes fragmentados puede haber jugado un rol en la disminución de algunas aves de la estepa arbustiva. Futuras investigaciones deberían medir el éxito reproductivo anual de hembras individuales y las tasas de supervivencia de juveniles y adultos.

scholarly journals Using Video to Monitor Predation at Black-Capped Vireo Nests

The Condor ◽  
2003 ◽  
Vol 105 (2) ◽  
pp. 348-357 ◽  
Author(s):  
Mike M. Stake ◽  
David A. Cimprich
Keyword(s):  
Nest Predation ◽  
Molothrus Ater ◽  
Time Lapse ◽  
Predation Rate ◽  
Video Monitoring ◽  
Fire Ants ◽  
Daily Survival Rate ◽  
Nest Failure ◽  
Fort Hood ◽  
Mammalian Predators

AbstractWe monitored 142 Black-capped Vireo (Vireo atricapillus) nests at Fort Hood, Texas, from 1998 to 2001 using time-lapse infrared videocameras to identify nest predators. We recorded 59 predator visits (where at least some of the nest contents were removed or destroyed), resulting in 48 depredated nests. Snakes and fire ants (Solenopsis spp.) were the leading predators, accounting for 18 (38%) and 15 (31%), respectively, of all depredated nests. We also identified a variety of avian (19% of depredated nests) and mammalian predators (11% of depredated nests). Despite intensive Brown-headed Cowbird (Molothrus ater) removal at Fort Hood, we recorded nine predator visits by females of this species, but only one resulted in nest failure. Although predator visits occurred at all hours, most (58%) took place at night. The daily predation rate was higher during the nestling stage than during incubation, partly due to the apparent inability of fire ants to prey upon vireo eggs. We monitored 435 nests without video; field assistants checked the contents of these every 4–5 days. The daily survival rate of these nests was not higher than the rate of nests monitored with video, evidence that video monitoring does not increase nest predation relative to monitoring by human visits to nests.Uso de Video para Observar la Depredación de Nidos de Vireo atricapillusResumen. De 1998 al 2001 monitoreamos 142 nidos de Vireo atricapillus en Fort Hood, Texas. Utilizamos cámaras de video de luz infrarroja para identificar a los depredadores de los nidos. Logramos grabar 59 visitas de depredación (donde al menos parte del contenido de los nidos fue removido o destruido); en éstas, 48 nidos fueron depredados. Los principales depredadores de los nidos de V. atricapillus fueron las serpientes y las hormigas de fuego (Solenopsis sp.). Del total de nidos depredados, 18 (38%) fueron depredados por serpientes y 15 (31%) por hormigas. También identificamos otros depredadores como algunas especies de aves (19% de los nidos depredados) y mamíferos (11% de los nidos depredados). A pesar de la campaña intensiva de erradicación de Molothrus ater en Fort Hood, registramos 9 visitas de depredación por parte de hembras de esta especie, pero sólo una de estas visitas resultó en el fracaso del nido. Aunque las visitas de depredación se dieron en cualquier momento, la mayoría (58%) ocurrió durante la noche. La tasa diaria de depredación fue más alta durante la etapa de crianza que durante la etapa de incubación, en parte debido a la aparente inhabilidad de las hormigas de fuego para depredar los huevos de Vireo atricapillus. Durante nuestra investigación, monitoreamos 435 nidos sin cámara de video; los asistentes de campo revisaron el contenido de estos nidos cada 4 ó 5 días. La tasa de sobrevivencia diaria de estos nidos no fue más alta que la de los nidos monitoreados con cámaras, mostrando que el monitoreo con éstas no incrementa la depredación de nidos con relación al monitoreo por visitas personales a los nidos.

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