Behavioural control of daily fattening in great tits (Parus major)

1996 ◽  
Vol 74 (9) ◽  
pp. 1612-1616 ◽  
Author(s):  
Kristjan Lilliendahl ◽  
Allan Carlson ◽  
Jonas Welander ◽  
Jan B. Ekman
Keyword(s):  
Foraging Behaviour ◽  
Parus Major ◽  
Mass Gain ◽  
Foraging Strategy ◽  
Time Of Day ◽  
Energy Reserves ◽  
Normal Pattern ◽  
Daily Cycle ◽  
State Dependent ◽  
The Cost

Many species of temperate-zone passerines show a pronounced daily cycle in body mass. Energy reserves are built up during the day and consumed the following night. The size of reserves is often viewed as a compromise between the risk of starvation and the cost of carrying an excessive fat load. This trade-off calls for state-dependent foraging behaviour, where current reserves and time of day are two crucial factors. The foraging strategy of the birds may then be reflected by the pattern of daily mass gain rate. We temporarily increased energy expenditure in captive great tits (Parus major) by experimentally lowering the overnight temperature. The birds' response to the treatment was to rapidly compensate for reduced morning reserves. Such an increased rate of mass gain suggests state-dependent foraging, and that some feeding opportunities are normally rejected. The rate of return to the normal pattern of fat accumulation suggests that in these birds, foraging is not constrained by physiological limitations.

Foraging Behaviour of Subordinate Great Tits (Parus major). Can Morphology Reduce the Cost of Subordination?

Ethology ◽  
2001 ◽  
Vol 107 (10) ◽  
pp. 877-888 ◽  
Author(s):  
M. Barluenga ◽  
E. Moreno ◽  
A. Barbosa
Keyword(s):  
Foraging Behaviour ◽  
Parus Major ◽  
The Cost

scholarly journals State-dependent learning influences foraging behaviour in an acoustic predator

2020 ◽  
Vol 163 ◽  
pp. 33-38 ◽  
Author(s):  
Claire T. Hemingway ◽  
Michael J. Ryan ◽  
Rachel A. Page
Keyword(s):  
Foraging Behaviour ◽  
State Dependent Learning ◽  
State Dependent ◽  
Dependent Learning

scholarly journals SCHEDULING IN A SINGLE-SERVER QUEUE WITH STATE-DEPENDENT SERVICE RATES

2019 ◽  
Vol 34 (4) ◽  
pp. 507-521
Author(s):  
Urtzi Ayesta ◽  
Balakrishna Prabhu ◽  
Rhonda Righter
Keyword(s):  
Optimal Policy ◽  
Arrival Rate ◽  
Complete Characterization ◽  
Single Server ◽  
Holding Costs ◽  
Release Times ◽  
State Dependent ◽  
Service Rates ◽  
Transient System ◽  
The Cost

We consider single-server scheduling to minimize holding costs where the capacity, or rate of service, depends on the number of jobs in the system, and job sizes become known upon arrival. In general, this is a hard problem, and counter-intuitive behavior can occur. For example, even with linear holding costs the optimal policy may be something other than SRPT or LRPT, it may idle, and it may depend on the arrival rate. We first establish an equivalence between our problem of deciding which jobs to serve when completed jobs immediately leave, and a problem in which we have the option to hold on to completed jobs and can choose when to release them, and in which we always serve jobs according to SRPT. We thus reduce the problem to determining the release times of completed jobs. For the clearing, or transient system, where all jobs are present at time 0, we give a complete characterization of the optimal policy and show that it is fully determined by the cost-to-capacity ratio. With arrivals, the problem is much more complicated, and we can obtain only partial results.

scholarly journals Cuttlefish show flexible and future-dependent foraging cognition

2020 ◽  
Vol 16 (2) ◽  
pp. 20190743 ◽  
Author(s):  
Pauline Billard ◽  
Alexandra K. Schnell ◽  
Nicola S. Clayton ◽  
Christelle Jozet-Alves
Keyword(s):  
Food Availability ◽  
Feeding Behaviour ◽  
Foraging Behaviour ◽  
Foraging Strategy ◽  
The Other ◽  
Foraging Activity ◽  
Experimental Conditions

Some animals optimize their foraging activity by learning and memorizing food availability, in terms of quantity and quality, and adapt their feeding behaviour accordingly. Here, we investigated whether cuttlefish flexibly adapt their foraging behaviour according to the availability of their preferred prey. In Experiment 1, cuttlefish switched from a selective to an opportunistic foraging strategy (or vice versa ) when the availability of their preferred prey at night was predictable versus unpredictable. In Experiment 2, cuttlefish exhibited day-to-day foraging flexibility, in response to experiencing changes in the proximate future (i.e. preferred prey available on alternate nights). In Experiment 1, the number of crabs eaten during the day decreased when shrimp (i.e. preferred food) were predictably available at night, while the consumption of crabs during the day was maintained when shrimp availability was unpredictable. Cuttlefish quickly shifted from one strategy to the other, when experimental conditions were reversed. In Experiment 2, cuttlefish only reduced their consumption of crabs during the daytime when shrimps were predictably available the following night. Their daytime foraging behaviour appeared dependent on shrimps' future availability. Overall, cuttlefish can adopt dynamic and flexible foraging behaviours including selective, opportunistic and future-dependent strategies, in response to changing foraging conditions.

Intertidal foraging by gentoo penguins in a macroalgal raft

2020 ◽  
Vol 32 (1) ◽  
pp. 43-44
Author(s):  
James B. McClintock ◽  
Charles D. Amsler ◽  
Margaret O. Amsler ◽  
William R. Fraser
Keyword(s):  
Environmental Change ◽  
Foraging Behaviour ◽  
Foraging Strategy ◽  
Foraging Strategies ◽  
Marion Island ◽  
Pygoscelis Papua ◽  
General Consensus ◽  
Foraging Tactics ◽  
Pygoscelid Penguins ◽  
Foraging Tactic

Foraging strategies in gentoo penguins (Pygoscelis papua) have been well studied (e.g. Croxall et al. 1988, Robinson & Hindell 1996, Lescroël et al. 2004, Takahashi et al. 2008, Xavier et al. 2017). The general consensus is this largest member of the three pygoscelid penguins displays both nearshore benthic and pelagic foraging tactics to consume combinations of crustaceans and fish. In a recent study, Carpenter-Kling et al. (2017) reported that gentoos at sub-Antarctic Marion Island displayed a novel foraging strategy that consisted of alternating typical lengthy foraging trips with much shorter nearshore afternoon trips. They suggest the latter foraging behaviour may be a response to suboptimal feeding conditions caused by local environmental change. This novel discovery reinforces the fact that, despite considerable study, not all foraging tactics in penguins have been documented. In this paper, we describe what we believe to be, yet another undocumented foraging tactic employed by gentoos.

Diving behaviour of an immature Kemp's ridley turtle (Lepidochelys kempii) from Gullivan Bay, Ten Thousand Islands, south-west Florida

2006 ◽  
Vol 86 (4) ◽  
pp. 919-925 ◽  
Author(s):  
Christopher R. Sasso ◽  
Wayne N. Witzell
Keyword(s):  
Foraging Behaviour ◽  
Diving Behaviour ◽  
Foraging Habitat ◽  
Normal Pattern ◽  
Lepidochelys Kempii ◽  
South West ◽  
Normal Period ◽  
Thousand Islands ◽  
Kemp's Ridley

We report on the first successfully deployed time-depth recorder on an immature Kemp's ridley turtle in a coastal foraging habitat in south-west Florida. The turtle exhibited three distinct dive patterns interpreted as: post release stress (26 h) post release transition (8 h) and normal (>34 h). The normal pattern consists of short periods on the surface followed by longer periods on the bottom in 2–3 m of water which we speculate is foraging behaviour. Overall, the turtle spent 94% of the time submerged during the normal period. The turtle spent significantly more time submerged at night than during the day, suggesting the turtle was resting. Night dives were consistently longer than dawn, day or dusk dives.

Changes in foraging behaviour during the infective stage of entomopathogenic nematodes

Parasitology ◽  
1995 ◽  
Vol 110 (5) ◽  
pp. 583-590 ◽  
Author(s):  
E. E. Lewis ◽  
S. Selvan ◽  
J. F. Campbell ◽  
R. Gaugler
Keyword(s):  
Metabolic Rate ◽  
Entomopathogenic Nematodes ◽  
Storage Period ◽  
Foraging Strategy ◽  
Heterorhabditis Bacteriophora ◽  
Steinernema Carpocapsae ◽  
Foraging Strategies ◽  
Infective Juvenile ◽  
Infective Stage ◽  
Energy Reserves

SUMMARYStudies of foraging strategies are often complicated by competing goals of the forager. In contrast, non-feeding infective juvenile entomopathogenic nematodes forage exclusively for a single host. Two questions were posed: (1) what is the relationship between metabolic rate, energy reserves and foraging strategy and (2) when a foraging strategy fails, will an infective-stage parasite switch strategies? Three species of entomopathogenic nematodes were stored in water and changes in their behaviour, metabolic rate, energy reserves, and infectivity were measured throughout the storage period. Steinernema carpocapsae ambushes insect hosts, whereas S. glaseri and Heterorhabditis bacteriophora cruise forage. Steinernema carpocapsae was least active and had the lowest metabolic rate. Heterorhabditis bacteriophora was more active and had the highest metabolic rate. Steinernema glaseri was most active and had an intermediate metabolic rate. Neither cruising species changed foraging strategy. Steinernema carpocapsae decreased nictation (a behaviour associated with ambushing only) and increased their locomotory rate. Any change in searching strategy occurred without assessment of the profitability or distribution of potential hosts, but the advantage this confers is unknown.

Opposite Changes in Plasma Testosterone and Corticosterone Levels Following a Simulated Territorial Challenge in Male Great Tits

Behaviour ◽  
2004 ◽  
Vol 141 (4) ◽  
pp. 451-467 ◽  
Author(s):  
Rianne Pinxten ◽  
Lutgarde Arckens ◽  
Els van Duyse ◽  
Marcel Eens ◽  
Veerle Darras
Keyword(s):  
Parus Major ◽  
Time Of Day ◽  
Behavioural Response ◽  
Egg Laying ◽  
Plasma Testosterone ◽  
Breeding Cycle ◽  
Territorial Defence ◽  
Breeding Stage ◽  
Simulated Territorial Intrusion ◽  
Territorial Intrusion

AbstractThe apparent ability of plasma testosterone (T) and corticosterone (B) levels to fluctuate rapidly in response to agonistic interactions, suggests that these hormones may play an important role in an animal's acute behavioural response during such interactions. In the present study, free-living male great tits, Parus major, were subjected to a simulated territorial intrusion (STI) during the egg laying, incubation and nestling stage of first broods. Plasma T and B levels of challenged males were compared to those of control males matched for breeding stage, day in breeding stage, and time of day. Plasma B levels were significantly higher in challenged males compared to control males during the egg laying and incubation stage but not during the nestling stage. On the other hand, challenged males had significantly lower plasma T levels than control males throughout the breeding cycle. While having low plasma T and elevated plasma B levels, challenged males showed a vigorous and unrelenting territorial response to the STI. Plasma T and B levels of challenged males did not correlate with the intensity of the behavioural response to the STI. These findings do not agree with the predictions of the 'challenge hypothesis' that males exposed to a territorial challenge while having breeding baseline T levels will respond with an increase in T or that T correlates with the intensity of aggression during a challenge. Together, our findings suggest a role for B rather than T in the regulation of territorial defence in male great tits.

Sign in / Sign up

Export Citation Format

Share Document