Quail eggs in artificial nests change their coloration when exposed to ambient conditions: implication for studies on nest predation

Quail eggs have been widely used in field experiments, mainly to study factors associated with the risk of nest predation. Some shortcomings of using quail eggs in this type of study have been previously addressed (e.g., these eggs might be too big for some predators of eggs of small birds). Here, we show experimental evidence of another shortcoming of the use of these eggs in field experiments. Quail eggs exposed to sunlight rapidly faded in colour after three days, both in the visible and UV spectra, and this change was related to the amount of solar radiation received. This caused changes in the camouflage of the eggs, which may be perceived by predators with different visual systems (dichromatic, trichromatic, and tetrachromatic (for both violet- and UV-sensitive species)). Therefore, the results of field studies of nest predation using quail eggs might be questioned in those cases in which the camouflage has been altered due to the rapid changes in coloration, as this can affect the resulting predation rates. We recommend that researchers planning to use quail eggs should perform a prospective assessment of changes in coloration of eggs exposed to environmental conditions in the nest sites used by the target species.

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An experimental approach to understanding the use of mistletoe as a nest substrate for birds: nest predation

Wildlife Research ◽

10.1071/wr06144 ◽

2008 ◽

Vol 35 (1) ◽

pp. 65 ◽

Cited By ~ 10

Author(s):

Stuart J. N. Cooney ◽

David M. Watson

Keyword(s):

Site Selection ◽

Nest Predation ◽

Nest Site ◽

Nest Site Selection ◽

Artificial Nests ◽

Bird Populations ◽

Nest Sites ◽

South Wales ◽

Eucalypt Woodland ◽

Substrate Variation

Recent research has documented an unprecedented diversity of birds using mistletoes as nest-sites, and a strong preference for nesting in mistletoes has recently been demonstrated for some species. The consequences and underlying reasons for this behaviour have not been evaluated, and it is unclear whether nests in mistletoes confer advantages compared with other available substrates. Nest predation is often cited as the most important factor regulating many bird populations and is thought to influence all aspects of nest-site selection. To evaluate whether nest predation may play a role in the widespread use of mistletoe as a nest-site, we conducted an artificial nest predation experiment in a eucalypt woodland in southern New South Wales, Australia. Artificial nests were modelled on noisy friarbird (Philemon corniculatus: Meliphagidae) nests, baited with a single quail egg and checked after four days. We used logistic regression to model the rate of depredation between plant substrates, and demonstrate that, in this experiment, mistletoe nests experienced a lower proportion of predation than eucalypt nests (51.5% versus 63.8% respectively). This finding suggests that predation may influence the widespread use of mistletoe as a nest-site in a range of habitats and regions. In addition to clarifying priorities for further work on mistletoe nesting, this finding has implications for studies of nest-site selection generally, with researchers encouraged to supplement between-substrate comparisons with direct measurements of within-substrate variation.

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Does Vertical Partitioning of Nest Sites Decrease Nest Predation?

The Auk ◽

10.1093/auk/117.2.409 ◽

2000 ◽

Vol 117 (2) ◽

pp. 409-415 ◽

Cited By ~ 1

Author(s):

Leonard R. Reitsma ◽

Christopher J. Whelan

Keyword(s):

Nest Predation ◽

Significant Variation ◽

Nest Site ◽

Coturnix Japonica ◽

Artificial Nests ◽

Ground Treatment ◽

Nest Sites ◽

Vertical Partitioning ◽

Pairwise Differences ◽

Experimental Treatments

Abstract Partitioning of nest heights among co-occurring species in response to nest predation has been proposed as a process that helps to structure avian species assemblages. In the experiment reported here, we used artificial nests baited with Japanese Quail (Coturnix japonica) eggs to test (1) whether both rate and final level of nest predation differed among nests placed at ground, shrub, and tree strata; and (2) whether vertical partitioning of nest sites among the three strata decreased nest predation. Although rates of nest predation increased from ground, to partitioned, to shrub, to tree strata, the only significant pairwise differences were between predation on ground nests versus all other treatments. The proportion of nests depredated at the conclusion of the experiment was lowest for the ground treatment, intermediate for the partitioned treatment, and highest for the shrub and tree treatments. Predation was significantly higher in 1988 than in 1989, and significant variation in predation occurred among five spatial replicates of the experimental treatments. Although the results show different susceptibilities to nest predation according to vegetative stratum, they show only a slight and nonsignificant reduction in nest predation as a consequence of vertical nest-site partitioning.

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Evaluating the Impact of Two Generalist Predators on the Leafhopper Erasmoneura vulnerata Population Density

Insects ◽

10.3390/insects12040321 ◽

2021 ◽

Vol 12 (4) ◽

pp. 321

Author(s):

Stefan Cristian Prazaru ◽

Giulia Zanettin ◽

Alberto Pozzebon ◽

Paola Tirello ◽

Francesco Toffoletto ◽

...

Keyword(s):

Field Experiments ◽

Field Studies ◽

Generalist Predators ◽

Predator Species ◽

Potted Plants ◽

Naturally Occurring ◽

Orius Majusculus ◽

Limited Effectiveness ◽

Pest Outbreaks ◽

The Impact

Outbreaks of the Nearctic leafhopper Erasmoneura vulnerata represent a threat to vinegrowers in Southern Europe, in particular in North-eastern Italy. The pest outbreaks are frequent in organic vineyards because insecticides labeled for organic viticulture show limited effectiveness towards leafhoppers. On the other hand, the naturally occurring predators and parasitoids of E. vulnerata in vineyards are often not able to keep leafhopper densities at acceptable levels for vine-growers. In this study, we evaluated the potential of two generalist, commercially available predators, Chrysoperla carnea and Orius majusculus, in suppressing E. vulnerata. Laboratory and semi-field experiments were carried out to evaluate both species’ predation capacity on E. vulnerata nymphs. The experiments were conducted on grapevine leaves inside Petri dishes (laboratory) and on potted and caged grapevines (semi-field); in both experiments, the leaves or potted plants were infested with E. vulnerata nymphs prior to predator releases. Both predator species exhibited a remarkable voracity and significantly reduced leafhopper densities in laboratory and semi-field experiments. Therefore, field studies were carried out over two growing seasons in two vineyards. We released 4 O. majusculus adults and 30 C. carnea larvae per m2 of canopy. Predator releases in vineyards reduced leafhopper densities by about 30% compared to the control plots. Results obtained in this study showed that the two predators have a potential to suppress the pest density, but more research is required to define appropriate predator–prey release ratios and release timing. Studies on intraguild interactions and competition with naturally occurring predators are also suggested.

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Do Repugnant Scents Increase Survival of Ground Nests? A Test with Artificial and Natural Duck Nests

The Canadian Field-Naturalist ◽

10.22621/cfn.v121i2.439 ◽

2007 ◽

Vol 121 (2) ◽

pp. 150

Author(s):

Vanessa B. Harriman ◽

Justin A. Pitt ◽

Serge Larivière

Keyword(s):

Human Hair ◽

Nest Predation ◽

Survival Rates ◽

Olfactory Cues ◽

Artificial Nests ◽

Treatment Groups ◽

Mammalian Predators ◽

High Predation ◽

Ground Nesting ◽

Predation Rates

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.

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Performance of the FMI cosine error correction method for the Brewer spectral UV measurements

Atmospheric Measurement Techniques ◽

10.5194/amt-11-5167-2018 ◽

2018 ◽

Vol 11 (9) ◽

pp. 5167-5180 ◽

Cited By ~ 4

Author(s):

Kaisa Lakkala ◽

Antti Arola ◽

Julian Gröbner ◽

Sergio Fabian León-Luis ◽

Alberto Redondas ◽

...

Keyword(s):

Error Correction ◽

Correction Method ◽

Uv Spectra ◽

Correction Coefficient ◽

Finnish Meteorological Institute ◽

Angular Response ◽

Error Correction Method ◽

Radiation Distribution ◽

Rapid Changes ◽

Relative Differences

Abstract. Non-ideal angular response of a spectroradiometer is a well-known error source of spectral UV measurements and for that reason instrument specific cosine error correction is applied. In this paper, the performance of the cosine error correction method of Brewer spectral UV measurements in use at the Finnish Meteorological Institute (FMI) is studied. Ideally, the correction depends on the actual sky radiation distribution, which can change even during one spectral scan due to rapid changes in cloudiness. The FMI method has been developed to take into account the changes in the ratio of direct to diffuse sky radiation and it derives a correction coefficient for each measured wavelength. Measurements of five Brewers were corrected for the cosine error and the results were compared to the reference travelling spectroradiometer (QASUME). Measurements were performed during the RBCC-E (Regional Brewer Calibration Center – Europe) X Campaign held at El Arenosillo, Huelva (37∘ N, 7∘ W), Spain, in 2015. In addition, results of site audits of FMI's Brewers in Sodankylä (67∘ N, 27∘ E) and Jokioinen (61∘ N, 24∘ E) during 2002–2014 were studied. The results show that the spectral cosine error correction varied between 4 and 14 %. After that the correction was applied to Brewer UV spectra the relative differences between the QASUME and the Brewer diminished even by 10 %. The study confirms that the method, originally developed for measurements at high latitudes, can be used at mid-latitudes as well. The method is applicable to other Brewers as far as the required input parameters, i.e. total ozone, aerosol information, albedo, instrument specific angular response and slit function are available.

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The watching eyes effect on charitable donation is boosted by fewer people in the vicinity

Letters on Evolutionary Behavioral Science ◽

10.5178/lebs.2016.52 ◽

2016 ◽

Vol 7 (2) ◽

pp. 9-12

Author(s):

Ryo Oda ◽

Ryota Ichihashi

Keyword(s):

Field Study ◽

Charitable Giving ◽

Field Experiments ◽

Field Studies ◽

Prosocial Behaviors ◽

Charitable Donation ◽

Charitable Donations ◽

Large Groups

Previous field experiments have found that artificial surveillance cues facilitated prosocial behaviors such as charitable donations and littering. Several previous field studies found that the artificial surveillance cue effect was stronger when few individuals were in the vicinity; however, others reported that the effect was stronger in large groups of people. Here, we report the results of a field study examining the effect of an artificial surveillance cue (stylized eyes) on charitable giving. Three collection boxes were placed in different locations around an izakaya (a Japanese-style tavern) for 84 days. The amount donated was counted each experimental day, and the izakaya staff provided the number of patrons who visited each day. We found that the effect of the stylized eyes was more salient when fewer patrons were in the izakaya. Our findings suggest that the effect of the artificial surveillance cue is similar to that of “real” cues and that the effect on charitable giving may weaken when people habituate to being watched by “real” eyes.

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An easy-to-use, low-cost evaporation protection to collect more reliable stable water isotope data with Teledyne ISCO portable samplers

10.5194/egusphere-egu21-2764 ◽

2021 ◽

Author(s):

Jana von Freyberg ◽

Julia L. A. Knapp ◽

Andrea Rücker ◽

Bjørn Studer ◽

Massimiliano Zappa ◽

...

Keyword(s):

Water Samples ◽

Isotope Fractionation ◽

Field Experiments ◽

Isotope Composition ◽

Ambient Conditions ◽

Storage Duration ◽

Full Size ◽

Isotope Data ◽

Protection Method ◽

Wide Range

<p>Off-the-shelf portable automatic water samplers, such as the 6712 full-size portable sampler (Teledyne ISCO, Lincoln, USA), are often used in remote locations to collect precipitation or streamwater for subsequent analysis of deuterium and oxygen-18. &#160;The bottles inside these automatic samplers remain open during the full duration of sampler deployment and the collected water samples can thus be subjected to evaporation and vapor exchange. &#160;Both processes are known to alter the isotope composition of the water sample, and thus the questions arise as to 1) how credible the isotope measurements from automatically collected water samples are and 2) how can these isotope effects in the automatic water sampler be reduced?</p><p>We evaluated these questions through laboratory and field experiments in which we quantified the change in isotope composition in the water samples with respect to ambient conditions (air temperature and relative humidity), storage duration, and sample volume.&#160; We found that isotope fractionation in the water samples was substantial under very warm and dry condition, when sample volumes are small or when sample storage exceeded 10 days. &#160;To address these problems, we have designed an evaporation protection method which modifies autosampler bottles using a syringe housing and silicone tube.&#160; We performed paired experiments with open vs. evaporation-protected bottles in Teledyne ISCO 6712 full-size portable samplers to evaluate our design. &#160;We could show that the evaporation protection successfully reduced isotope fractionation in the water samples for storage durations of up to 24 days and for a wide range of ambient conditions; e.g., while deuterium concentrations in the water samples in open bottles changed by ca. 3&#8240; under very warm and dry conditions, no isotope effect was measured in the bottles equipped with the evaporation protection. Because our design is very cost efficient it can easily be implemented to upgrade Teledyne ISCO&#8217;s 6712 full-size portable samplers or other similar devices for collecting more reliable isotope data.</p>

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Optimizing Sowing Depth of Tef for Irrigated Mediterranean Conditions: From Laboratory to Field Studies

Agronomy ◽

10.3390/agronomy10121983 ◽

2020 ◽

Vol 10 (12) ◽

pp. 1983

Author(s):

Shiran Ben-Zeev ◽

Shane Kerzner ◽

Onn Rabinovitz ◽

Yehoshua Saranga

Keyword(s):

Field Experiments ◽

Field Studies ◽

Field Trials ◽

Eragrostis Tef ◽

Sowing Depth ◽

New Crops ◽

Different Depths ◽

Plant Emergence ◽

Increasing Demand ◽

Mediterranean Conditions

Developing new crops adapted to arid conditions is a promising approach to meet the increasing demand for food production under expanding aridity. Tef [Eragrostis tef (Zucc.) Trotter] is a C4 cereal crop cultivated mainly in Ethiopia and the Horn of Africa, and known for its high resilience to stressful environments. Due to their tiny size, tef seeds are traditionally sown by broadcasting and lightly covering with soil. Under semiarid Mediterranean conditions, a deeper sowing may guarantee seedling establishment while saving on irrigation water. The objective of this study was, therefore, to determine the effects of sowing depth on tef emergence, development, lodging, and productivity. Tef seeds were sown at different depths in test tubes and pots, and in two field experiments. In tubes and pots, time from sowing to emergence increased about twofold and emergence rate decreased in the deepest sowing (3 cm) treatment compared to controls (0 cm). In the pot and field trials, deep sowing (3 cm) significantly reduced plant height, shoot and root biomass, and lodging. Sowing depths of 1–2 cm allowed successful plant establishment while not exacting penalties on plant emergence or development; hence this range appears to be optimal for sowing irrigated tef.

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The fate of detergent surfactants in sewer systems

Water Science & Technology ◽

10.2166/wst.1995.0248 ◽

1995 ◽

Vol 31 (7) ◽

pp. 321-328 ◽

Cited By ~ 16

Author(s):

E. Matthijs ◽

G. Debaere ◽

N. Itrich ◽

P. Masscheleyn ◽

A. Rottiers ◽

...

Keyword(s):

Fatty Alcohol ◽

Half Life ◽

Laboratory Tests ◽

Field Experiments ◽

Sewage Treatment ◽

Field Studies ◽

Municipal Sewage ◽

Alcohol Ethoxylate ◽

Rapid Reduction ◽

Laboratory Findings

The fate of detergent surfactants in the sewer can be studied both in laboratory tests and in field experiments. The laboratory studies can be used to determine the rate of disappearance of a test molecule as a function of residence time and estimate its half-life in a given habitat. In addition, important information can be obtained on the mechanism of degradation. Field studies can determine the actual environmental concentrations of surfactants in raw sewage which can then be compared with the expected concentration based on consumption volumes. The difference between the measured and predicted concentration provides an estimate for the disappearance of the test chemical during its travel in the sewer and confirms the results of the laboratory tests. This paper focuses on the fate of a number of important representative anionic, nonionic and cationic surfactants, in the sewer. The results of laboratory die-away studies showed that, in general, the half-life for disappearance in the sewer was in the order of hours for Fatty Alcohol Ethoxylate (AE), Fatty Alcohol Ethoxy Sulphate (AES) and Di-Ethyl-Ester Di-methyl-Ammonium Chloride (DEEDMAC). These laboratory findings for AES were confirmed by monitoring actual raw sewage reaching municipal sewage treatment plants. In addition, a field study demonstrated that the concentration of glucose amides (GA) is considerably reduced during its travel in the sewer. These complementary laboratory and field studies provide key information for the safety assessment of surfactants. They demonstrate that the concentration of surfactants can be significantly reduced in the sewer resulting in a rapid reduction of the environmental loading, which is particularly important in environmental situations where inadequate or no sewage treatment exists.

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Foliar and Root Absorption of Atrazine Applied Postemergence to Giant Foxtail

Weed Science ◽

10.1017/s0043174500031441 ◽

1969 ◽

Vol 17 (2) ◽

pp. 251-256 ◽

Cited By ~ 17

Author(s):

Lafayette Thompson ◽

F. W. Slife

Keyword(s):

Field Experiments ◽

Soil Surface ◽

Dry Weight ◽

Field Studies ◽

Simulated Rainfall ◽

Root Absorption ◽

Giant Foxtail ◽

Setaria Faberii ◽

Chamber Studies ◽

Growth Chamber Studies

In growth chamber studies, high relative humidity and rewetting crystalline spray deposits of 2-chloro-4-ethylamino-6-isopropylamino-s-triazine (atrazine) increased absorption by and phytotoxicity to giant foxtail (Setaria faberii Herrm.), but phytotoxicity was restricted to expanded (unrolled) leaves unless some atrazine was absorbed by the roots. Though phytotoxicity was increased by simulated rainfall when root absorption was prevented, an appreciable number of the plants were killed only when atrazine residues were washed into the soil. In field studies, atrazine applied to a wet soil surface was as effective as the same rate of atrazine foliarly applied. In other field experiments, atrazine applied to giant foxtail on a wet soil and followed by simulated rainfall reduced stand and dry weight, but on a dry soil and not followed by simulated rainfall, atrazine reduced dry weight less and did not reduce stand. These results are due to root absorption of atrazine from wet soil. Spray additives increased phytotoxicity.

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