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

Author(s):  
Martin Sládeček ◽  
Kateřina Brynychová ◽  
Esmat Elhassan ◽  
Miroslav Salek ◽  
Veronika Janatová ◽  
...  

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 the 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 444 nests of red-wattled lapwings (Vanellus indicus), a ground-nesting shorebird, for a sum of 7828 days to estimate a nest predation rate, and continuously monitored 230 of these nests for a sum of 2779 days to reveal how the timing of predation changes over the day and season in a sub-tropical desert. We found that 312 nests (70%) hatched, 76 nests (17%) were predated, 23 (5%) failed for other reasons and 33 (7%) had an unknown fate. Daily predation rate was 0.95% (95%CrI: 0.76% – 1.19%), which for a 30-day long incubation period translates into ~25% (20% – 30%) chance of nest being predated. Such a predation rate is low compared to most other avian species. Predation events (N = 25) 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 when mid-day ground temperatures exceeded 45°C. Whether the diel activity pattern of resident predators undeniably changes across the breeding season and whether the described predation patterns hold for other populations, species and geographical regions awaits future investigations.

Author(s):  
Martin Sládeček ◽  
Kateřina Brynychová ◽  
Esmat Elhassan ◽  
Miroslav Salek ◽  
Veronika Janatová ◽  
...  

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.


The Condor ◽  
2003 ◽  
Vol 105 (2) ◽  
pp. 348-357 ◽  
Author(s):  
Mike M. Stake ◽  
David A. Cimprich

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.


2008 ◽  
Vol 25 (2) ◽  
pp. 165-171 ◽  
Author(s):  
Charles Duca ◽  
Miguel Ângelo Marini

Several factors, including the site where the colony was established and number of active nests can influence directly or indirectly the breeding success of colonial birds. The red-rumped cacique, Cacicus haemorrhous (Linnaeus, 1766), is a passerine (Icteridae) that breeds in colonies in different environments. The objective of this study was to evaluate the breeding success of red-rumped cacique in relation to three environments (lake edge, forest and swamp) in which colonies were established in an Atlantic Forest reserve in southeast Brazil. Seven colonies from the three environments were monitored during the breeding season of 2001. Overall probability of nest survival was 40.5%. We found that colonies established in the swamp presented higher nest survival than the others and the ones in the lake edge had lower survival. Nest predation was the most important cause of nest failure, representing 46.5% of all nest losses. Other failure causes were abandonment and fall of nests, representing 6.6% and 6.1% of the losses, respectively. Red-rumped cacique had higher success breeding in colonies located in the swamp.


The Condor ◽  
2001 ◽  
Vol 103 (3) ◽  
pp. 521-529 ◽  
Author(s):  
Viviana Massoni ◽  
Juan Carlos Reboreda

Abstract We investigated whether the synchrony and proximity of nests of Yellow-winged Blackbirds (Agelaius thilius) provided protection against nest predation or brood parasitism by Shiny Cowbirds (Molothrus bonariensis). We analyzed the effect of the temporal aggregation of nests on the daily probability per nest of predation, desertion, egg punctures, and parasitism throughout the breeding season. The probabilities of nest predation and nest desertion increased through the breeding season. The temporal aggregation of nests was negatively associated with the probability of nest desertion, egg punctures, and parasitism, but there was no association with the probability of nest predation. We also analyzed the effect of the number of close neighbor nests on the daily probability per nest of predation, desertion, egg punctures, and brood parasitism. The spatial aggregation of nests was negatively associated with the probability of nest failure and brood parasitism, but there was no association with the probability of egg punctures. We discuss whether dilution effect or group defense, two mechanisms proposed to explain the antipredatory advantages of colonial nesting, are likely to apply to our system. El Número de Vecinos Espaciales y Temporales Disminuye la Probabilidad de Pérdida del Nido y de Parasitismo por Molothrus bonariensis en Colonias de Agelaius thilius Resumen. Se investigó si la sincronía y la proximidad de nidos del Agelaius thilius proveyó protección ante la depredación del nido y el parasitismo de cría por Molothrus bonariensis. Se analizó el efecto de la agregación temporal de nidos sobre la probabilidad diaria por nido de depredación, abandono, picaduras y parasitismo a lo largo de la temporada reproductiva. Las probabilidades de predación y abandono del nido aumentaron a medida que avanzó la temporada reproductiva. La agregación temporal de nidos estuvo negativamente asociada con la probabilidad de abandono, picaduras y parasitismo pero no se observó asociación de ésta con la probabilidad de predación. También se analizó el efecto del número de nidos vecinos cercanos sobre la probabilidad de pérdida del nido y de parasitismo de cría. La agregación espacial de nidos estuvo asociada negativamente con la probabilidad de pérdida del nido y de parasitismo de cría pero no se observó una asociación de ésta con la probabilidad de picadura de huevos. Se discute si el efecto de dilución o la defensa grupal, dos mecanismos propuestos para explicar los beneficios antipredatorios de la nidificación colonial, son probables de ocurrir en este sistema.


2003 ◽  
Vol 107 (2) ◽  
pp. 149-154 ◽  
Author(s):  
Sherah L. VanLaerhoven ◽  
David R. Gillespie ◽  
Bernard D. Roitberg

2007 ◽  
Vol 121 (2) ◽  
pp. 150
Author(s):  
Vanessa B. Harriman ◽  
Justin A. Pitt ◽  
Serge Larivière

Ground-nesting birds typically experience high predation rates on their nests, often by mammalian predators. As such, researchers and wildlife managers have employed numerous techniques to mitigate nest predation. We investigated the use of scents as repellents to deter predators from both artificial and natural ground nests. Survival rates of artificial nests did not differ among six groups of substances (Wald ?2 df = 5 = 4.53, P < 0.48); however the chronology of predation among groups differed. A commercial Coyote urine based deterrent (DEER-D-TERTM), human hair, and Worcestershire sauce were depredated faster than the control (F4,5 = 40.3, P < 0.001). Nest survival of natural nests differed among those groups tested (Wald ?2 df = 2 = 11.8, P < 0.005); the eight mothball treatment decreased survival (Wald ?2 df = 1 = 11.5, P < 0.005), which indicated that novel smells may attract predators or result in duck nest abandonment when coupled with natural duck scent. Chronologies of predation events among treatment groups were not different for natural nests (F2,3 = 1.9, P = 0.22). These findings indicate an interaction between novel scents and predator olfactory cues.


2017 ◽  
Vol 28 (2) ◽  
pp. 293-301 ◽  
Author(s):  
VÁCLAV ZÁMEČNÍK ◽  
VOJTĚCH KUBELKA ◽  
MIROSLAV ŠÁLEK

SummaryOnly a few studies have assessed the predation risk on artificially marked nests, or have examined ways of marking nests to avoid destruction by machinery. Until now, however, neither type of study has directly addressed this apparent trade-off experimentally. The impact of marking the nests of Northern Lapwing Vanellus vanellus with thin 2 m-long conspicuous bamboo poles with the top end highlighted with reflective red or orange spray has been tested for three years in two breeding areas of waders in the Czech Republic. A total of 52 pairs of nests on agricultural land, with each pair consisting of one marked nest and one unmarked reference counterpart nest, were monitored for 2004 nest-days until hatching, agricultural operations or failure. The results proved that marking itself does not result in increased nest predation. The nests found in the early incubation stage were under higher threat of depredation, irrespective of the presence of marking. Our results show that it is possible to find a finely-tuned trade-off in nest marking of ground-nesting birds between risk of damage by agricultural machinery and risk of increased nest predation. Our positive experience with Northern Lapwing, and episodically with three other wader species in the Czech Republic, suggests that this direct nest protection could be used effectively for a wider variety of ground-nesting birds.


2010 ◽  
Vol 8 (4) ◽  
pp. 893-898 ◽  
Author(s):  
Leo G. Nico

Several Pterygoplichthys species, members of the Neotropical catfish family Loricariidae, have been widely introduced outside their native ranges. In this paper, I present observations on the diel activity pattern of non-native Pterygoplichthys, tentatively identified as P. disjunctivus, with respect to their attachment and grazing on endangered Florida manatees, Trichechus manatus latirostris. The study was conducted in December 2009 at Volusia Blue Spring, an artesianal spring system in the St. Johns River basin, Florida (USA). Supplemented by information gathered during previous visits to the spring site, this study revealed that adult Pterygoplichthys are active throughout the diel period (day, twilight and night). However, juvenile Pterygoplichthys were largely nocturnal and only at night did they consistently join adults in attaching to manatees. The juveniles generally remain hidden during the day, probably responding to presence of diurnal predators, mainly birds. Differences in diel behaviors among different Pterygoplichthys size classes in Florida are consistent with published observations on loricariids inhabiting clearwater streams within their native ranges.


2012 ◽  
Vol 90 (6) ◽  
pp. 694-703 ◽  
Author(s):  
H. Gillis ◽  
B. Gauffre ◽  
R. Huot ◽  
V. Bretagnolle

Avian eggs need to be laid in protected environments to develop and survive. Nest predation is known as the main cause of breeding failure for many birds, but nest microclimate conditions are also important for embryo development. These two selective pressures are particularly marked in ground-nesting birds. Vegetation height has been shown to be a critical factor for nest-site selection in ground-nesting birds because it can counteract predation and overheating simultaneously. It is therefore difficult to disentangle the respective influences of these risks on selection of a particular nest vegetation height. To develop a conceptual framework for understanding and predicting the relative effects of vegetation on predation and nest microclimate during a breeding season, we used vegetation height to manipulate differentially these two risks. We therefore exposed artificial nests to a wide range of vegetation heights, replicated the experimental tests during spring, and manipulated egg color to estimate predation risk. We confirmed that tall vegetation is relevant to protect unattended eggs against both risks. Whereas predation risk is stable for a given vegetation height, overheating risk presents inter- and intra-seasonal variations. Therefore, over a breeding season, for a given vegetation height, the respective strengths of the two risks are unbalanced and depends on egg coloration. The breeding strategy of ground-nesting birds thus should have been shaped by both selective pressures, but the ultimate choice may depend on the species-specific laying dates and alternative behavioral strategies for protecting the clutch. This study provides new perspectives to investigate avian parental behaviour.


The Auk ◽  
1988 ◽  
Vol 105 (3) ◽  
pp. 553-564 ◽  
Author(s):  
Dianne H. Brunton

Abstract The reproductive investment strategies of the sexes during the breeding season are detailed for Killdeer (Charadrius vociferus), a monogamous plover. I measured the energy investments of the sexes in reproductive, mating, and parental effort. As predicted, males expend more mating effort than females; however, the sexes expend equal amounts of parental effort. Total energy expenditure in reproductive effort (mating and parental effort) during a successful nesting attempt was also equal for the sexes. However, early parental effort expenditures by females, early mating effort expenditures by males, and high rates of nest failure combine to result in female reproductive energy expenditures being significantly higher over the breeding season. This suggests that energy expenditure alone is not adequate for accurate comparisons of the relative investments of the sexes. Studies investigating male and female investments need to consider the degree and pattern of nest failures along with patterns of energy expenditure. The advantages to male and female Killdeer of sharing parental care is demonstrated using adult removal experiments. In general, a deserted parent expends more energy in parental effort than a bi-parental parent and has significantly lower reproductive success. However, males are able to hatch chicks, whereas females lose or abandon their nests within a few days of mate removal. Thus, monogamy in Killdeer appears to result from high nest failure rates, the necessity of two parents for any reproductive success, and the generalizable nature of Killdeer parental care.


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