Seasonal Differences in Contaminant Accumulation in Neotropical Migrant and Resident Songbirds

The seasonal variations of raindrop size distribution (DSD) and rainfall are investigated using three-year (2016–2018) observations from a two-dimensional video disdrometer (2DVD) located at a suburban station (40.13°N, 116.62°E, ~30 m AMSL) in Beijing, China. The annual distribution of rainfall presents a unimodal distribution with a peak in summer with total rainfall of 966.6 mm, followed by fall. Rain rate (R), mass-weighted mean diameter (Dm), and raindrop concentration (Nt) are stratified into six regimes to study their seasonal variation and relative rainfall contribution to the total seasonal rainfall. Heavy drizzle/light rain (R2: 0.2~2.5 mm h−1) has the maximum occurrence frequency throughout the year, while the total rainfall in summer is primarily from heavy rain (R4: 10~50 mm h−1). The rainfall for all seasons is contributed primarily from small raindrops (Dm2: 1.0~2.0 mm). The distribution of occurrence frequency of Nt and the relative rainfall contribution exhibit similar behavior during four seasons with Nt of 10~1000 m−3 registering the maximum occurrence and rainfall contributions. Rainfall in Beijing is dominated by stratiform rain (SR) throughout the year. There is no convective rainfall (CR) in winter, i.e., it occurs most often during summer. DSD of SR has minor seasonal differences, but varies significantly in CR. The mean values of log10Nw (Nw: mm−1m−3, the generalized intercept parameter) and Dm of CR indicate that the CR during spring and fall in Beijing is neither continental nor maritime, at the same time, the CR in summer is close to the maritime-like cluster. The radar reflectivity (Z) and rain rate (?) relationship (Z = ?R?) showed seasonal differences, but were close to the standard NEXRAD Z-R relationship in summer. The shape of raindrops observed from 2DVD was more spherical than the shape obtained from previous experiments, and the effect of different axis ratio relations on polarimetric radar measurements was investigated through T-matrix-based scattering simulations.

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Benthic invertebrate assemblages and leaf‐litter breakdown along the eucrenal–hypocrenal ecotone of a rheocrene spring in Central Italy: Are there spatial and seasonal differences?

Ecohydrology ◽

10.1002/eco.2289 ◽

2021 ◽

Author(s):

Antonio Di Sabatino ◽

Luca Coscieme ◽

Francesco Paolo Miccoli ◽

Giovanni Cristiano

Keyword(s):

Leaf Litter ◽

Central Italy ◽

Benthic Invertebrate ◽

Litter Breakdown ◽

Seasonal Differences ◽

Leaf Litter Breakdown ◽

Invertebrate Assemblages

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Potential displacement of the native Tenuisvalvae notata by the invasive Cryptolaemus montrouzieri in South America suggested by differences in climate suitability

Bulletin of Entomological Research ◽

10.1017/s000748532100033x ◽

2021 ◽

pp. 1-11

Author(s):

Larissa F. Ferreira ◽

Christian S. A. Silva-Torres ◽

Jorge B. Torres ◽

Robert C. Venette

Keyword(s):

Biological Control ◽

South America ◽

Prey Availability ◽

Ecological Factors ◽

Growth Conditions ◽

Cryptolaemus Montrouzieri ◽

Seasonal Differences ◽

Ladybird Beetle ◽

Ecoclimatic Index ◽

Climate Suitability

Abstract Tenuisvalvae notata (Mulsant) (Coccinellidae) is a predatory ladybird beetle native to South America. It specializes in mealybugs prey (Pseudococcidae), but relatively little is known about its ecology. In contrast, the ladybird beetle Cryptolaemus montrouzieri Mulsant (Coccinellidae) is indigenous to Australia and has been introduced to many countries worldwide including Brazil for biological control of mealybugs. The potential impacts of these introductions to native coccinellids have rarely been considered. The software CLIMEX estimated the climate suitability for both species as reflected in the Ecoclimatic Index (EI). Much of South America, Africa, and Australia can be considered climatically suitable for both species, but in most cases, the climate is considerably more favorable for C. montrouzieri than T. notata, especially in South America. The CLIMEX model also suggests seasonal differences in growth conditions (e.g. rainfall and temperature) that could affect the phenology of both species. These models suggest that few locations in South America would be expected to provide T. notata climatic refugia from C. montrouzieri. Although other ecological factors will also be important, such as prey availability, this analysis suggests a strong potential for displacement of a native coccinellid throughout most of its range as a consequence of the invasion by an alien competitor.

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Differences in Depredation by Small Predators Limit the Use of Plasticine and Zebra Finch Eggs in Artificial-Nest Studies

The Condor ◽

10.1093/condor/103.1.180 ◽

2001 ◽

Vol 103 (1) ◽

pp. 180-183 ◽

Cited By ~ 2

Author(s):

Thomas J. Maier ◽

Richard M. Degraaf

Keyword(s):

Small Mammals ◽

Zebra Finch ◽

House Sparrow ◽

Peromyscus Leucopus ◽

Passer Domesticus ◽

Field Studies ◽

Taeniopygia Guttata ◽

Artificial Nest ◽

Neotropical Migrant ◽

Passerine Species

Abstract Small mammals, such as mice and voles, have been implicated as major egg predators of Neotropical migrant passerines by field studies using soft plasticine eggs or the very small eggs of Zebra Finch (Taeniopygia guttata). Nevertheless, the effort required to depredate these commonly used egg surrogates may be less than that required to depredate the larger, thicker-shelled eggs of most passerine species. To compare the depredation of these surrogates to that of the eggs of a mid-sized passerine by a ubiquitous small predator, we exposed dissimilar pairs of plasticine, Zebra Finch, and House Sparrow (Passer domesticus) eggs to captive white-footed mice (Peromyscus leucopus). Plasticine eggs were marked by mice more than either kind of real egg, and Zebra Finch eggs were breached more often than House Sparrow eggs. We conclude that the use of either plasticine or Zebra Finch eggs may lead to overestimation of the ability or proclivity of small mammals to actually depredate the eggs of most passerines.

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Seasonal differences in migration strategies of Red Kites (Milvus milvus) wintering in Spain

Journal of Ornithology ◽

10.1007/s10336-021-01918-5 ◽

2021 ◽

Author(s):

Jorge García-Macía ◽

Javier Vidal-Mateo ◽

Javier De La Puente ◽

Ana Bermejo ◽

Rainer Raab ◽

...

Keyword(s):

Spring Migration ◽

Great Variability ◽

Autumn Migration ◽

Seasonal Differences ◽

North Eastern ◽

Wintering Areas ◽

Satellite Transmitters ◽

Migration Strategies ◽

Migratory Movements ◽

Milvus Milvus

AbstractRed Kite shows a great variability in its migration strategies: most individuals in north-eastern Europe are migrants, but there is also a growing number of sedentary individuals. Here, we tagged 49 Red Kites wintering in Spain with GPS/satellite transmitters between 2013 and 2020 to study the autumn and spring migration between the breeding or summering areas in Central Europe and the wintering quarters in Spain. In first place, differences between immatures and adults were found for spring migration. Adults began the spring migration towards the northeast in February–March while the immature individuals began to migrate significantly later and showing a wider date range (February-June). Adults also takes significantly less days to arrive at their destinations (12 ± 5 days) and cover more distance per day (134.2 ± 37.1 km/day) than immatures (19 ± 11 days and 98.9 ± 21.2 km/day). In second place, we also found differences between spring and autumn migration (excluding immatures). Spring migrations were clearly faster and with less stopovers days than autumn migrations. Autumn migration began between mid-October and late November and two different behaviours were observed: most birds made a quick migration direct to the wintering areas with only some days of stopovers, but others prolonged the migration with long stops along the route. These results highlight a great variation in the migratory movements of Red Kite, not only according to age but also between individuals and seasons.

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