Nest Disturbance Research Articles

Biología reproductiva de anátidos (Familia Anatidae) en la Laguna de Zumpango, Estado de México

La Laguna de Zumpango se ha convertido en un humedal urbano fuertemente influenciado por actividades humanas, lo que ha puesto en riesgo su biodiversidad. Esta laguna es uno de los últimos relictos de la Cuenca de México que aún alberga una gran diversidad de aves acuáticas y varias especies la utilizan como zona de anidación. En este estudio describimos algunos aspectos de la biología reproductiva de aves de la familia Anatidae en la Laguna de Zumpango. Registramos cinco especies que anidan en esta zona: el pijije canelo (Dendrocygna bicolor), el pato mexicano (Anas platyrhynchos diazi), la cerceta canela (Anas cyanoptera), el pato tepalcate (Oxyura jamaicensis), y una especie que había sido considerada como visitante de invierno: el pato friso (Anas strepera). La temporada reproductiva de 2015 inició en febrero y culminó en septiembre. Describimos el sustrato utilizado para la construcción del nido, el tamaño de nidada para tres especies y el éxito de eclosión para una. Determinamos entre las principales causas de fracaso reproductivo el abandono del nido, la reducción de la nidada y la infertilidad de los huevos. Reportamos por primera vez cuidado parental cooperativo para O. jamaicensis. La Laguna de Zumpango es un hábitat primordial para la reproducción de aves acuáticas como los patos, que ven afectado su éxito de anidación por la continua transformación y perturbación de su hábitat. Sugerimos medidas que ayuden a mitigar la perturbación de las aves y sus nidos durante la temporada reproductiva y para mantener las zonas de anidación.

Interannual Golden Eagle (Aquila chrysaetos) Nest-Use Patterns in Central Utah: Implications for Long-Term Nest Protection

Abstract Land managers regularly use temporal nest protections to reduce the likelihood of raptor nest disturbance or abandonment, but guidelines are not consistent across management boundaries. We assessed alternative nest use (i.e., egg-laying) and nest spacing at 28 Golden Eagle (Aquila chrysaetos) territories that were monitored ≥25 yr between 1976 and 2013 (all except seven territories were monitored annually without interruption). Territories contained 1–8 nests (x¯ = 2.9), and average spacing between alternative nests was 0.5 km. Inspection of 21 territories monitored for 26–38 yr without interruption suggested eagles used individual nests an average of every 3.3 yr, laid eggs in any nest within territories an average of every 1.8 yr, and switched nests between 43.3% of consecutive nesting attempts (i.e., egg-laying in discrete breeding seasons). Protecting individual nests for 7 yr, or protecting all nests within a territory for 4 yr after the last documented use of any nest when alternative nests...

An agent-based model to evaluate recovery times and monitoring strategies to increase accuracy of sea turtle population assessments

Green sea turtles are threatened globally, and some populations continue to decline while others are recovering. Assessing recovery status largely depends on monitoring efforts that encounter sea turtles on nesting beaches and sample nesters, nests, or both. Monitoring nesting beaches provides an imperfect index of true population level changes in abundance due to demographic time lags and inter-annual variability in nesting. But, it is still unclear how much and in which direction nesting beach indices diverge from true population status. To address this concern, we used demographic parameters estimated from the Hawaiian green turtle population to develop and implement the green sea turtle agent-based model (GSTABM) to simulate stable and transient population dynamics, monitoring and population assessment. We subjected the virtual populations to sub-adult, adult, and nest disturbances and simulated the monitoring process of observing nesters and nests with error. The GSTABM simulates population-level processes of nester abundance and corresponds with observed data from Hawaii. In simulating 100 years of recovery, populations began to increase but did not fully return to pre-disturbance levels in adult and nester abundance, population growth or nester recruitment. The accuracy of estimated adult abundance was influenced by population trajectory and impacts, and was not sensitive to increasing detection probability. The accuracy of estimated recruitment improved with increasing detection levels, but depended on the impact legacy. The GSTABM is an important tool to determine relationships with monitoring, population assessment, and the underlying biological processes that drive changes in the population. The ultimate purpose of the GSTABM is to be an operating model with which to evaluate optimal monitoring strategies for nesting beach surveys that will enhance accuracy of population assessments, allowing agencies to invest in the most cost-effective monitoring efforts.

First record of nestling relocation by adult Gyrfalcons (Falco rusticolus) following nest collapse

ABSTRACT Nest collapse has been documented in many bird species, with little discussion of adult behavior following collapse. We present evidence of a partial collapse of a Gyrfalcon (Falco rusticolus) nest during the nestling period and the subsequent adult response. A nest camera captured the nest collapse and showed one adult Gyrfalcon holding a live nestling in its beak before leaving the nest. Later, we found the surviving nestling alive in an alternate nest 5 m from the original nest, presumably transported there by the adult. We believe this is the first report of an adult Gyrfalcon moving a nestling to a new location following nest disturbance. We place this observation into a context of Gyrfalcon nesting behavior described in published sources. The continued use of nest cameras may provide additional documentation and insight into this behavior and its prevalence in birds.

Worker Size and Nest Defense in Solenopsis invicta (Hymenoptera: Formicidae)

Abstract Workers of the red imported fire ant, Solenopsis invicta Buren (Hymenoptera: Formicidae), range in size from ≈0.5 to 1.5 mm in headwidth. Such size variation is thought to enable a more efficient division of labor, because some worker sizes may be better suited to performing particular tasks. Here, I focus on the task of nest defense, where efficiency and effectiveness may depend on having appropriately sized workers respond to particular types of threats. Specifically, I tested whether the size of responding workers differs between two magnitudes of nest disturbance (light, insect-like versus heavy, vertebrate-like), and I investigated how both sting length and the amount of venom workers contain, key defensive traits, vary with worker size. Workers responding to heavy, vertebrate-like nest disturbances were larger than those responding to light, insect-like disturbances. Between the light and heavy disturbances, the proportion of minor (small) workers responding dropped, whereas that of major (large) workers increased five-fold. Although the relationship between sting length and worker size is not directly proportional, the average sting length of majors is ≈0.20 mm (or 40%) greater than that of minors, with little overlap in range. The relationship between worker size and the amount of venom they contain is also positive. So, vertebrate-magnitude nest disturbances are met with greater proportions of large S. invicta workers than are insect-magnitude disturbances, and these larger workers bring with them longer stings and larger venom arsenals, which may increase their effectiveness against such relatively large, thicker-skinned threats.

Colony Budding and its Effects on Food Allocation in the Highly Polygynous Ant, Monomorium pharaonis

AbstractTo advance our understanding of the causes and the consequences of budding (colony multiplication by fragmentation of main nests), we investigated nest movement in the facultatively polydomous Pharaoh ant, Monomorium pharaonis. Demographic data revealed that Pharaoh ants are highly polygynous and have a relatively low worker to queen ratio of 12.86. Budding experiments demonstrated that the number of available bud nests has a significant effect on colony fragmentation and increasing the number of bud nests resulted in smaller colony fragments. The overall distribution among bud nests was uneven, even though there was no evidence that the different life stages and castes partitioned unevenly among the bud nests and the analysis of individual colonies revealed no evidence of an uneven split in any of the colonies. This demonstrates that Pharaoh ants have the ability to exert social control over colony size and caste proportions during budding, which may contribute to their success as an invasive ant. The intensity of nest disturbance had a significant effect on whether or not the ants migrated into bud nests. Major disturbance resulted in the ants abandoning the source nest and migrating to bud nests and minor disturbance did not stimulate the ants to abandon the source nest. The results of the successive budding experiment which allowed the ants the opportunity to bud into progressively smaller nest fragments demonstrate that Pharaoh ants maintain a preferred minimum group size of 469 ± 28 individuals. Food allocation experiments utilizing protein marking revealed that nest fragmentation in Pharaoh ants has no negative impact on intracolony food distribution. Overall, our results suggest that nest units in the Pharaoh ant behave like cooperative, rather than competitive, entities. Such cooperation is most likely facilitated by the fact that individuals in all bud nests are genetically related, remain in close proximity to each other, and may continue to exchange individuals after budding.

Marbled Murrelet nest predation risk in managed forest landscapes: dynamic fragmentation effects at multiple scales

The effects of forest fragmentation on bird populations have been studied primarily as static phenomena. Yet when forests are allowed to regenerate, local edge contrast and landscape matrix composition change with time, and we would expect fragmentation effects to change accordingly. Describing this process is critical for the conservation of avian species sensitive to forest fragmentation, including the Marbled Murrelet (Brachyramphus marmoratus), a seabird threatened by ongoing harvest of old-growth forest nesting habitat. We experimentally assessed potential murrelet nest predation probability in four regions of southwestern British Columbia, Canada. We compared the fates of 448 simulated murrelet nests at paired edge and interior treatments, at sites with "hard" edges (recent clearcuts), "soft" edges (regenerating forest), and natural edges (i.e., riparian areas). Motion-sensitive digital nest cameras enabled us to focus on known predators of real nests, and patterns of nest fates did not differ between real and simulated nests. Using information-theoretic model selection (AIC) with the combined data set (116 sites), we assessed effects at patch (approximately 13 ha), landscape (approximately 1700 ha), and regional (approximately 96000 ha) scales. Nest disturbance probability at hard edges was 2.5 times that of interior sites, but soft edges had less than half the disturbance probability of interiors. There was no edge effect at natural edges. At the landscape scale, overall avian disturbance risk declined by as much as 50% with increasing amounts of regenerating forest in the surrounding matrix. These results indicate that initially negative fragmentation effects decrease as forests regenerate, at both patch and landscape scales. There was no evidence that these patterns differed between regions. Predator surveys suggested that Steller's Jays drive patterns of nest predation risk at the regional scale. Assuming that corvids are the most important predators, larger reserves of habitat will lessen negative hard-edge effects. Smaller reserves should be embedded in a protective matrix of regenerating forest to reduce predation risk at both patch and landscape scales. Our results suggest that dynamic fragmentation effects are generalizable across widespread regions and can be broadly applied to both murrelet management and the conservation of old-growth forest-breeding birds in general.

Modelling human impacts on the Tasmanian wedge-tailed eagle ( Aquila audax fleayi)

The wedge-tailed eagle is Australia’s largest bird of prey and one of the largest eagles in the world. Aquila audax fleayi is an endemic Tasmanian subspecies isolated for 10,000 years from the nominate subspecies on the Australian mainland. The Tasmanian wedge-tailed eagle is classified nationally and at a State level as endangered due to its small number of breeding pairs, low breeding success and high rate of mortality from unnatural causes. The subspecies experiences mortality throughout its range from shooting, poisoning, trapping, road accidents, electrocutions and collisions with wind turbines, aircraft, fences and overhead wires, which we term ‘un-natural mortality’. A portion of the subspecies’ range is managed for timber production, which can lead to disturbance of nest sites and the loss of nest trees. We use a model of the eagle population from the Bass District in northeast Tasmania to explore the relative importance of different sources of mortality and nesting habitat loss, and the potential for mitigating impacts associated with unnatural mortality, disturbance, nesting habitat loss and human access to forests. We create a habitat map including suitable nest sites and link it to a dynamic landscape population model based on life history traits and disturbance responses. Using the program RAMAS-Landscape, we model alternative forest management scenarios, ranging from no timber harvesting and a natural wildfire regime, to scenarios prescribing native forest harvesting and regeneration and different levels of conversion of native forest to plantation under the same natural wildfire regime. The results indicate that the Tasmanian wedge-tailed eagle is sensitive to unnatural mortality, plantation establishment and native forest harvesting. The predicted decline over the next 160 years (∼65%) will most likely be driven largely by loss of current and potential future nest sites associated with harvesting activities, exacerbated by unnatural mortality in the wider landscape. Interventions that minimise unnatural mortality, reduce nest disturbance, and retain breeding habitat and nest sites may improve the prospects for the subspecies in the Bass District. If nest disturbance and unnatural mortality continue at the rates modelled here, the species appears to face a high risk of declining substantially in the region.

Osprey: Worldwide Sentinel Species for Assessing and Monitoring Environmental Contamination in Rivers, Lakes, Reservoirs, and Estuaries

In the United States, many fish and wildlife species have been used nationwide to monitor environmental contaminant exposure and effects, including carcasses of the bald eagle (Haliaeetus leucocephalus), the only top avian predator regularly used in the past. Unfortunately, bald eagles are sensitive to investigator intrusion at the nest. Thus, the osprey (Pandion haliaetus) is evaluated as a potential sentinel species for aquatic ecosystems. Several characteristics support the choice of the osprey as a sentinel species, including: (1) fish-eating diet atop the aquatic food web, (2) long-lived with strong nest fidelity, (3) adapts to human landscapes (potentially the most contaminated), (4) tolerates short-term nest disturbance, (5) nests spatially distributed at regular intervals, (6) highly visible nests easily located for study, (7) ability to accumulate most, if not all, lipophilic contaminants, (8) known sensitivity to many contaminants, and (9) nearly a worldwide distribution. These osprey traits have been instrumental in successfully using the species to understand population distribution, abundance, and changes over time; the effects of various contaminants on reproductive success; how contaminants in prey (fish on biomass basis) contribute to egg concentrations (i.e., biomagnification factors); and spatial residue patterns. Data summarized include nesting population surveys, detailed nesting studies, and chemical analyses of osprey egg, organ, blood, and feather samples for contaminants that bioaccumulate and/or biomagnify in aquatic food webs; and biochemical evaluations of blood and various organs. Studies in the United States, Canada, Mexico, Europe, and elsewhere have shown the osprey to be a useful sentinel species for monitoring selected environmental contaminants, including some emerging contaminants in lakes, reservoirs, rivers, and estuaries.

Predators at Nests of the Western Slaty Antshrike (Thamnophilus atrinucha)

Predation is the primary cause of nest loss in most passerine species. While nest predation is important, the predator community and behaviors of parents and predators during predation events are poorly documented. I witnessed one and videotaped four predation events at nests of Western Slaty Antshrikes (Thamnophilus atrinucha) in central Panama. Predators included a snake (Pseustes poecilonotus), a monkey (white-faced capuchin [Cebus capucinus]), and three species of birds. Predators spent little time at the nest, yet some returned repeatedly to the same nest. Parents also returned several times to nests after the predation event and parental behaviors varied depending on the predator. Nest disturbance was not an accurate indicator of predator type.

Effect of disturbance on laying pattern and hatchability of feral helmet guinea fowl (<i>numida meleagris galleata</i> pallas) egg.

The effect of breeding nest disturbance and hatchability potential of feral helmet guinea-fowl was studied. Ten (10) breeding nests were identified and monitored for number of eggs laid per week for eight weeks within the Kainji Lake Basin. Eggs were collected as a form of disturbance at different percentages i.e 0, 50, 60, 80 and 100. The eggs were later incubated and tested for their hatchability. The bird's egg laying pattern changed drastically in response to egg collection. The trend in nests where 100%, 80% and 60% of their eggs were collected presented sharp decrease in number of egg laid per week immediately after the collection. Incidentally, there was significant difference (P

Removal of a nest-mate elicits an age-dependent increase in plasma corticosterone of nestling Black-legged Kittiwakes

en

Effect of horseshoe crab spawning density on nest disturbance and exhumation of eggs: A simulation study

Because the Delaware Bay horseshoe crab (Limulus polyphemus) population is managed to provide for dependent species, such as migratory shorebirds, there is a need to understand the process of egg exhumation and to predict eggs available to foraging shorebirds. A simple spatial model was used to simulate horseshoe crab spawning that would occur on a typical Delaware Bay beach during spring tide cycles to quantify density-dependent nest disturbance. At least 20% of nests and eggs were disturbed for levels of spawning greater than one third of the average density in Delaware Bay during 2004. Nest disturbance increased approximately linearly as spawning density increased from one half to twice the 2004 level. As spawning density increased further, the percentage of eggs that were disturbed reached an asymptote of 70% for densities up to 10 times the density in 2004. Nest disturbance was heaviest in the mid beach zone. Nest disturbance precedes entrainment and begins the process of exhumation of eggs to surface sediments. Model predictions were combined with observations from egg surveys to estimate a snap-shot exhumation rate of 5–9% of disturbed eggs. Because an unknown quantity of eggs were exhumed and removed from the beach prior to the survey, cumulative exhumation rate was likely to have been higher than the snap-shot estimate. Because egg exhumation is density-dependent, in addition to managing for a high population size, identification and conservation of beaches where spawning horseshoe crabs concentrate in high densities (i.e., hot spots) are important steps toward providing a reliable food supply for migratory shorebirds.

An inexpensive method for remotely monitoring nest activity

ABSTRACT In studies of avian nest success, investigators often face the difficult task of periodically checking nest status while at the same time limiting observer influence on nest survival. Remotely monitoring nests using temperature data loggers is one method that allows for continuous data capture regarding nest status (i.e., active vs. inactive) without the negative effects associated with repeated nest checks. We used small temperature data loggers (Thermochron iButtons) to remotely monitor nests of Long-billed Curlews (Numenius americanus) in northeastern Nevada. Data loggers programmed to record temperature at 10-min and 20-min intervals were placed in curlew nests. Data loggers were set to collect data throughout the nesting cycle to determine onset of incubation and timing of nest failure. On average, Long-billed Curlews began incubating approximately 3 d after the first egg was laid and onset of incubation coincided with the laying of the third egg. iButtons allowed us to determine when incubation was terminated in 17 of 23 unsuccessful Long-billed Curlew nests, including 13 of 17 depredated nests. The presence of iButtons in Long-billed Curlew nests did not affect daily survival rate, egg hatchability or rate of nest abandonment. iButtons are an efficient and practical means for remotely monitoring nests of large egg-laying birds, such as the Long-billed Curlew. SINOPSIS En estudios de exito de anidamiento, los investigadores muchas veces se encuentran con la dificultad de examinar el nido, tratando de limitar la infuencia del observador en la sobrevivencia de las aves. Uno de los metodos de monitoreo remoto es el uso de bitacoras electronicas de temperatura que permiten tomar datos de forma continua en un nido (e.g., activo vs inactivo) sin los efectos negativos asociados con el examen periodico del mismo. Utilizamos bitacoras electronicas de temperatura (Thermochron iButtons) para monitorear nidos de chorlo (Numenius americanus) en el norte de Nevada. El instrumento se programo para tomar la temperatura dentro del nido a intervalos de 10 a 20 minutos. El instrumento se utilizo para tomar datos a traves del ciclo de anidamiento del ave para determinar el comienzo de la incubacion y el momento en que el nido fuera abandonado. En promedio los chorlos comienzan a incubar aproximadamente tres dias despues de puesto el primer huevo, lo que coincide con la puesta del tercer huevo. iButtons permitio determinar el final del periodo de incubacion de 13 de 17 nidos depredados. La presencia del instrumento en los nidos de chorlo no afecto la tasa diaria de sobrevivencia, tampoco el eclosionamiento o la tasa de abandono. Las bitacoras utilizadas son eficientes y ademas una forma practica de monitorear a remoto los nidos de aves grandes tales como el chorlo estudiado.

Egg care by termite soldiers

The handling and transportation of eggs by soldiers of Prorhinotermes simplex after a nest disturbance is described. The soldiers, apart from performing alarm and defensive activities, tried to handle the eggs on the open surface. They often succeeded in lifting an egg or even a group of eggs, and then searched for a nest entrance. They either entered the nest to come out without the egg(s) within a while, or they passed the egg(s) onto a pseudergate waiting in the opening. As a result, all eggs were rapidly evacuated. Laboratory experimentation showed that pseudergates and nymphs try to deposit the eggs in a dark shelter, whereas the soldiers tend to transfer the eggs to nestmates and drop them after a while if no other termite accepts them.

Use of Radio-Telemetry to Test for Investigator Effects on Nesting Mallards, <em>Anas platyrhynchos</em>

We examined the effects of investigator activity on hatching rates of radio-marked wild female Mallards (Anas platyrhynchos), and evaluated the efficacy of radio-telemetry to minimize nest disturbance, characterize vegetation at nest sites, and mark nests for later relocation. Differences in hatching rates between birds that were flushed once (experimental) and those never flushed (control) approached significance (P = 0.086). However, hatching rates did not differ (P = 0.588) between the two groups when nests where investigator activity caused abandonment (30% of experimental nests) were removed from analysis. If the nest remained active, flushing the bird and visiting the nest once did not appear to increase the likelihood of the nest being depredated. We were able to locate 92% of radio-telemetry marked nests (control) after the female was no longer tending the nest. Radio-telemetry provides a technique to collect relatively unbiased nesting data for Mallards without disturbing the female.

Nest predation in a fragmented Afrotropical forest: evidence from natural and artificial nests

Nest predation accounts for a substantial share of nest failure and low reproductive success in most tropical songbirds. Normally, forest fragmentation leads to an increase in nest predation pressure due to reduced cover, fewer (and poorer) nest sites and predator influxes from the surrounding habitats. To test this hypothesis, we studied natural nesting behaviour and nest success of the white-starred robin ( Pogonocichla stellata) in seven Afrotropical forest fragments differing in size and level of habitat disturbance. Based on data from 12 nests, we estimate that 29% of all natural nests initiated by the robins survive to produce fledglings across all fragments. We also conducted an experiment using artificial (plasticine) model-eggs to reveal potential predators and compare relative predation rates amongst fragments. This experiment revealed that small mammals might be the major predators on robin nests at the egg-stage. In addition, it showed that the highest incidences of nest disturbance during this stage were in the most heavily disturbed fragment. This was presumably attributable to an influx of mammalian predators from the surrounding habitats as forest degradation created suitable habitats for them. Such an infiltration was recently reported in this study site. Both nest placement and microhabitat did not significantly affect depredation levels in our experiment. This suggests that depredation was predominantly incidental (i.e., predators mainly encountered nests fortuitously while foraging for other food items), where the likelihood of encountering a nest largely depended upon the prevalence of the principal potential predators – the small mammals.

Absence of kin discrimination in a ponerine ant

Kinship theory implies that individual social Hymenoptera should be able to identify kin. We tested kin discrimination in the polygynous ponerine ant Gnamptogenys striatula. Mate choice experiments showed that individuals did not pair according to kinship. Experiments on matriline discrimination revealed that workers did not preferentially groom, transport (after nest disturbance) or cannibalize (after starvation) larvae on the basis of kin, when both related and unrelated larvae were present. These results show the absence of kin discrimination for the criteria and experimental conditions used. The lack of kin discrimination during mate choice in G. striatula can be explained by male dispersion and female philopatry, which reduces the likelihood of mating between siblings and of kin-based mate choice reflected in incest avoidance. The lack of matriline discrimination by workers may reflect permanent intracolony mutualism or the high cost of discrimination. Finally, it appears that the absence of kin discrimination in such contexts in G. striatula is not incompatible with kinship theory and may have been secondarily selected during social evolution. Copyright 2002 The Association for the Study of Animal Behaviour. Published by Elsevier Science Ltd. All rights reserved.

Variability in soil chemistry and arbuscular mycorrhizal fungi in harvester ant nests: the influence of topography, grazing and region

Harvester ants are important disturbance agents across western North America, but the effects of ant disturbances on soils may vary considerably with topography and land use. We examined how soil properties and arbuscular mycorrhizal (AM) fungi in harvester ant nests varied across spatial scales according to topography, grazing regime and region. Soils from undisturbed areas were compared with nest disturbances created by two species of harvester ants, Pogonomyrmex occidentalis on shortgrass steppe in Colorado and P. rugosus on Chihuahuan desert grassland in New Mexico, in 1996 and 1997. Nests of both ant species were enriched with NO3 –-N, total P and roots colonized by AM fungi. Soil moisture was higher in P. rugosus' nests and lower in P. occidentalis' nests compared to surrounding areas. Soil pH was consistently lower in ant nests. Broad-scale factors such as grazing, topography and site affected most soil properties in and away from ant nests. Site exerted a strong influence on soil organic matter, pH and moisture. Within sites, topography had a significant affect on pH. Mycorrhizal colonization was influenced by site and topography in 1996 only, a substantially wetter year at both sites. Lastly, nutrient levels were largely determined by the fine-scale effects of ant disturbances. Principal components analysis revealed that, after removing site-level effects, harvester ants have similar functional roles in creating soil heterogeneity in these two different semiarid ecosystems.

The reproductive flight phenology of a neotropical ant assemblage

Summary1. Alate flights reflect an ant colony's investment in sexual reproduction and dispersal yet little is known about community‐wide patterns of alate phenology. Two Malaise traps (for 2 years) and two light traps (for 1 year) were used to explore the flight phenologies of 22 common neotropical species from Barro Colorado Island, Panama.2. The traps caught 23 182 individuals and 286 species/morphospecies. The two trap methods shared only 18 species. Samples also differed in sexual composition: light trap samples were 80% female, Malaise trap samples were 2.6% female.3. Of 22 common species, all but one flew over half the year, with about half flying every month of the year. These data, combined with a literature review, suggest a latitudinal gradient in alate flight season: one north temperate assemblage (42°N) averaged 1.6 lunar months per species. The ever‐warm tropical year provides a larger flight window that allows a diversity of phenologies, from continuous to strongly pulsed.4. Rainfall was correlated with alate flights in one‐third of the species. Quantile regression suggested that high weekly rainfall was necessary but not sufficient to produce alate flights in about a quarter of the species.5. By decreasing the number of nests releasing alates on a given day, long flight seasons may lower the probability of finding a mate. At the same time, long flight seasons may increase the opportunity of finding vacant nest sites. High population densities and high incidence of nest disturbance in this community may ameliorate the first cost while enhancing the second benefit.