Parental attendance of Chestnut Thrush reduces nest predation during the incubation period: compensation for low nest concealment?

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.

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STUDIES OF THE TIME BUDGET AND DAILY ACTIVITY OF COMMON EIDER SOMATERIA MOLLISSIMA DURING INCUBATION

10.18411/0004-2021-00294 ◽

2021 ◽

Author(s):

GRIGORI M. TERTITSKI ◽

EVGENY V. SEMASHKO ◽

ALEXANDER E. CHERENKOV ◽

VLADIMIR Y. SEMASHKO

Keyword(s):

Incubation Period ◽

Nest Predation ◽

Daily Activity ◽

White Sea ◽

Average Duration ◽

Time Budget ◽

Common Eider ◽

Somateria Mollissima ◽

The Common

In the Common Eider Somateria mollissima, only females incubate the clutch over a period of 25–28 days. Determining their schedule of nest absence, how long they are away, how often, and where they go can be problematic. They must also avoid nest predation while tending to their own needs. We used geolocators to investigate the behavior of incubating females on forested islands in Dolgaya Guba Bay (65°03′N, 035°47′E), White Sea, Russia. Data were obtained for 12 females: three in 2015 and 2016, four in 2017, and two in 2018. During the entire incubation period, females left their nests for the sea 12–28 times. The average duration at sea was 331.0 ± 53.8 min, including 261.1 ± 47.9 min during the darkest hours in otherwise 24-hour daylight. The patterns are similar to those of eiders nesting in lower, nonpolar latitudes, where nights are dark.

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Nest relief in the cryptically-incubating semipalmated sandpiper is quick but vocal

10.1101/2021.07.30.454457 ◽

2021 ◽

Author(s):

Martin Bulla ◽

Christina Muck ◽

Daniela Tritscher ◽

Bart Kempenaers

Keyword(s):

Incubation Period ◽

Monitoring System ◽

Nest Predation ◽

Continuous Monitoring ◽

Low Risk ◽

Biparental Care ◽

Semipalmated Sandpiper ◽

Risk Of Predation ◽

Calidris Pusilla ◽

Semipalmated Sandpipers

Biparental care requires coordination between parents. Such coordination might prove difficult if opportunities to communicate are scarce, which might have led to the evolution of elaborate and noisy nest relief rituals in species facing a low risk of predation. However, whether such conspicuous rituals also evolved in species that avoid predation by relying on crypsis remains unclear. Here, we used a continuous monitoring system to describe nest relief behavior during incubation in an Arctic-breeding shorebird with passive nest defense, the semipalmated sandpiper (Calidris pusilla). We then explored whether nest relief behavior provides information about parental cooperation and predicts incubation effort. We found that incubating parents vocalized twice as much before the arrival of their partner than during other times of incubation. In 75% of nest reliefs, the incubating parent left the nest only after its partner had returned and initiated the nest relief. In these cases, exchanges were quick (25s, median) and shortened over the incubation period by 0.1 – 1.4s per day (95%CI), suggesting that parents became more synchronized. However, nest reliefs were not cryptic. In 90% of nest reliefs, at least one parent vocalized, and in 20% of nest reliefs, the incubating parent left the nest only after its returning partner called instantaneously. In 30% of cases, the returning parent initiated the nest relief with a call; in 39% of these cases, the incubating partner replied. If the partner replied, the next off-nest bout was 1 – 4hr (95%CI) longer than when the partner did not reply, which corresponds to an 8 – 45% increase. Our results indicate that incubating semipalmated sandpipers, which rely on crypsis to avoid nest predation, have quick but acoustically conspicuous nest reliefs. Our results also suggest that vocalizations during nest reliefs may be important for the division of parental duties.

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Spotted Towhee Population Dynamics in a Riparian Restoration Context

The Condor ◽

10.1093/condor/109.4.721 ◽

2007 ◽

Vol 109 (4) ◽

pp. 721-733

Author(s):

Stacy L. Small ◽

Frank R. Thompson ◽

Geoffrey R. Geupel ◽

John Faaborg

Keyword(s):

Nest Predation ◽

Large Scale ◽

Habitat Restoration ◽

Multiple Scales ◽

Nest Survival ◽

Breeding Habitat ◽

Population Increase ◽

Adult Survival ◽

Host Nest ◽

Nest Concealment

Abstract We investigated factors at multiple scales that might influence nest predation risk for Spotted Towhees (Pipilo maculatus) along the Sacramento River, California, within the context of large-scale riparian habitat restoration. We used the logistic-exposure method and Akaike's information criterion (AIC) for model selection to compare predator search, predator abundance, restoration, and temporal effects hypotheses. Our candidate models represented restoration, temporal, nest activity, nest concealment, agriculture, and flood effects. Restoration sites did function as breeding habitat, with nest survival comparable to mature forest sites and some young being produced. The best-supported models contained the covariates cowbird young in host nest and calendar date. All supported models contained the covariate cowbird young, the only variable with a strong effect. In contrast to our prediction, nest survival increased with cowbird young in the nest, implicating adult cowbirds in nest predation events. Nest survival declined throughout the breeding season and increased marginally with nest concealment. We calculated the finite rate of population increase (λ), using a model that incorporated nest success estimates for parasitized and unparasitized nests, double brooding, the locally observed cowbird parasitism rate for Spotted Towhees, number of young fledged from successful parasitized and unparasitized nests, adult survival and a range of juvenile survival values, estimated as percentages of adult survival. Values of λ did not approach the replacement level of one, indicating that this population is not self-sustaining. We recommend extensive habitat restoration in the floodplain landscape, ideally in conjunction with cowbird control, to reduce nest predation and parasitism pressures.

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Nest-predation at the edge: an experimental study contrasting two types of edges in the dry Chaco, Paraguay

Ecography ◽

10.1034/j.1600-0587.2001.240612.x ◽

2001 ◽

Vol 24 (6) ◽

pp. 742-750 ◽

Cited By ~ 7

Author(s):

Lena M. Eriksson ◽

Lars Edenius ◽

Veronika Areskoug ◽

Dennis A. Meritt Jr

Keyword(s):

Experimental Study ◽

Nest Predation

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Effect of Temperature on ADP-Induced Platelet Aggregation

Thrombosis and Haemostasis ◽

10.1055/s-0038-1647758 ◽

1973 ◽

Vol 29 (01) ◽

pp. 183-189

Author(s):

C. A Praga ◽

E. M Pogliani

Keyword(s):

Platelet Aggregation ◽

Incubation Period ◽

Room Temperature ◽

Important Variable ◽

Practical Significance ◽

Effect Of Temperature ◽

Induce Platelet Aggregation ◽

Cuvette Holder ◽

Exact Temperature

SummaryTemperature represents a very important variable in ADP-induced platelet aggregation.When low doses of ADP ( < 1 (μM) are used to induce platelet aggregation, the length of the incubation period of PRP in the cuvette holder of the aggregometer, thermostatted at 37° C, is very critical. Samples of the same PRP previously kept at room temperature, were incubated for increasing periods of time in the cuvette of the aggregometer before adding ADP, and a significant decrease of aggregation, proportional to the length of incubation, was observed. Stirring of the PRP during the incubation period made these changes more evident.To measure the exact temperature of the PRP during incubation in the aggre- gometer, a thermocouple device was used. While the temperature of the cuvette holder was stable at 37° C, the PRP temperature itself increased exponentially, taking about ten minutes from the beginning of the incubation to reach the value of 37° C. The above results have a practical significance in the reproducibility of the platelet aggregation test in vitro and acquire particular value when the effect of inhibitors of ADP induced platelet aggregation is studied.Experiments carried out with three anti-aggregating agents (acetyl salicyclic acid, dipyridamole and metergoline) have shown that the incubation conditions which influence both the effect of the drugs on platelets and the ADP breakdown in plasma must be strictly controlled.

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Colchicine Uptake and Binding by Human Platelets

Thrombosis and Haemostasis ◽

10.1055/s-0038-1651471 ◽

1975 ◽

Vol 34 (03) ◽

pp. 780-794 ◽

Cited By ~ 4

Author(s):

Dianne M Kenney ◽

Francis C Chao ◽

James L Tullis ◽

Gail S Conneely

Keyword(s):

Time Dependence ◽

Incubation Period ◽

Binding Sites ◽

Silicone Oil ◽

Cold Treatment ◽

Human Platelets ◽

Temperature Dependent

SummaryThe uptake and binding of antimitotic alkaloid colchicine has been demonstrated in washed preparations of human platelets. A silicone oil technique was adapted so that both uptake and binding of 14C-colchicine were examined in the same platelet preparations. The time dependence and amount of colchicine taken up and bound by different platelet preparations during a 90 to 120 min incubation period were highly reproducible. Both colchicine uptake and binding by intact platelets, and colchicine binding by preparations of lysed platelets were specific and temperature dependent. Colchicine uptake was slowly reversible. Magnesium and GTP enhanced colchicine binding by lysed platelet preparations but calcium decreased binding.Exposure of platelets to either cold (4° C) or to thrombin, which disrupt platelet microtubules, produced significant increases in colchicine uptake and binding. The thrombin effect was maximal at 37° C and resulted in a greater increase in uptake and binding than that produced by either cold treatment alone or, by cold treatment followed by incubation with thrombin at 37° C. The amount of increase in uptake and binding produced by thrombin was independent of both thrombin (1–5 Units/109 platelets) and colchicine concentrations (1–50 × 10−6M).It is postulated that thrombin may initiate the formation, or make available, colchicine binding sites (microtubule subunits) within platelets.

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Elevated nest predation risk promotes offspring size variation in birds with prolonged parental care.

10.32942/osf.io/h2mpw ◽

2019 ◽

Author(s):

Gretchen F. Wagner ◽

Emeline Mourocq ◽

Michael Griesser

Keyword(s):

Predation Risk ◽

Reproductive Cycle ◽

Perceived Risk ◽

Nest Predation ◽

Bird Species ◽

Size Variation ◽

Egg Laying ◽

Offspring Size ◽

Natural Predation ◽

Risk Spreading

Predation of offspring is the main cause of reproductive failure in many species, and the mere fear of offspring predation shapes reproductive strategies. Yet, natural predation risk is ubiquitously variable and can be unpredictable. Consequently, the perceived prospect of predation early in a reproductive cycle may not reflect the actual risk to ensuing offspring. An increased variance in investment across offspring has been linked to breeding in unpredictable environments in several taxa, but has so far been overlooked as a maternal response to temporal variation in predation risk. Here, we experimentally increased the perceived risk of nest predation prior to egg-laying in seven bird species. Species with prolonged parent-offspring associations increased their intra-brood variation in egg, and subsequently offspring, size. High risk to offspring early in a reproductive cycle can favour a risk-spreading strategy particularly in species with the greatest opportunity to even out offspring quality after fledging.

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DETERMINATION OF AFTER-RIPENING PERIOD AND HORMONAL RESPONSE OF OROBANCHE SOLMSII C.D. CLARKE SEEDS

Ecoprint An International Journal of Ecology ◽

10.3126/eco.v11i1.149 ◽

1970 ◽

Vol 11 (1) ◽

Author(s):

A. Bista ◽

G. B. Khattri ◽

B. D. Acharya ◽

S. C. Srivastava

Keyword(s):

Growth Hormone ◽

Seed Germination ◽

Key Words ◽

Incubation Period ◽

Seed Set ◽

Summer Season ◽

Conditioning Period ◽

Root Parasite ◽

One Year

To find out the ability of Orobanche seeds to germinate immediately after seed set, seeds were germinated periodically at an interval of three months for one year in GR24. Some Orobanche seeds were capable of germination immediately after seed set but most required about nine months as after ripening or incubation period to be able to germinate. The phenomenon of after ripening in Orobanche seeds could be taken as an ecological measure to dormant over following unfavorable wet summer season. The growth hormone studies on Orobanche seed germination have shown that GA3 at a concentration of 100 ppm substantially enhanced seed germination when applied during pre-conditioning period. NAA showed some stimulatory effect at 0.5 - 1.0 ppm when applied during post-conditioning period but the hormone if applied during pre-conditioning period inhibited the germination. Kinetin failed to stimulate the germination at all the concentrations tested. Key words: Germination, root-parasite, hormone. Ecoprint Vol.11(1) 2004.

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