Optimal central place foraging flights in relation to wind

Abstract

Many flying animals, like birds feeding their young, make commuting flights between a central place and foraging areas in the surroundings. Such central place foraging (CPF) represents a special case of foraging theory. We use simple geometry and trigonometry to analyse CPF flight performance (a round-trip cycle of outward flight from the central place and inward flight back along the reverse track) in relation to wind. In addition to considering the situation of a constant and uniform wind field, we take into account two factors that are likely to apply in many CPF situations under natural conditions: (a) that animals carry a load that will increase the energy expenditure during the inward flight and (b) that they may fly at different altitudes during out-and inward flights in the wind gradient above the ground or sea surface. Four main predictions emerge: (1) efficiency of CPF flights will be reduced with increasing wind speed, and foraging at the longest ranges is expected under low wind speeds. (2) A preference for CPF flights in crosswinds is expected in a constant and uniform wind field. (3) Carrying a load during the inward flight makes it optimal to fly with a small component of following winds during this flight while the outward flight will have a corresponding component of opposed winds. (4) With a steep wind gradient (e.g. over rough terrain) providing much shelter from wind at the lowest altitudes, predicted behaviour may change from crosswind preference to a preference for flights along the head/tailwind axis (at low altitude into headwinds and high altitude in tailwinds). Detailed tests of predictions for CPF flights in relation to wind will be important for understanding constraints and adaptations in animal responses to wind and for evaluating consequences of changing wind regimes in animal movement ecology. Keywords Optimal flight • Wind effect on flight • Commuting flights • Central place foraging Zusammenfassung Optimale "central place"-Nahrungsflüge im Verhältnis zum Wind. Viele fliegende Tiere, wie beispielsweise Vögel, die ihre Jungen füttern, unternehmen Pendelflüge zwischen einem zentralen Platz und Nahrungsgebieten in der Umgebung. Dieses sogenannte "central place foraging" (CPF) stellt einen besonderen Fall der Nahrungssuche dar. Wir nutzten einfache Geometrie und Trigonometrie, um die CPF-Flugleistung (Hinflug ausgehend von einem zentralen Punkt und Rückflug auf dem gleichen Flugweg) im Verhältnis zu Wind zu analysieren. Zusätzlich zur Betrachtung einer konstanten und uniformen Windumgebung berücksichtigten wir zwei Faktoren, die sehr wahrscheinlich in vielen CPF-Situationen unter natürlichen Bedingungen eine Rolle spielen, (a) dass Tiere eine Last tragen, die ihren Energieaufwand auf dem Rückflug erhöht und (b) dass i.e. in unterschiedlichen Höhen während der Hin-und Rückflüge im Windgradienten über der Boden-oder Meeresoberfläche fliegen können. Vier Hauptprognosen gehen daraus hervor: (1) die Effizienz von CPF-Flügen wird mit steigender Windgeschwindigkeit reduziert und die längsten...

A central place foraging seabird flies at right angles to the wind to jointly optimize locomotor and olfactory search efficiency

“…[6,9,12]) perspectives. Based on theoretical models, crosswind flight is predicted to be the optimal anemotactic strategy in a wind field that remains constant over the spatial and temporal domain of use [23]. These theoretical predictions are fairly intuitive, because birds flying with the assistance of advantageous tail winds during the outward section of the flight would have to face the costs of returning to the colony with headwinds.…”

“…These theoretical predictions are fairly intuitive, because birds flying with the assistance of advantageous tail winds during the outward section of the flight would have to face the costs of returning to the colony with headwinds. Due to the longer duration of the headwind homeward flight and the extra food load, the costs would exceed the benefits, making this strategy less profitable than crosswind flight [23].…”

Temporal invariance of social‐ecological catchments

“…In ecology, concepts such as central place foraging theory recognize the importance of spatial proximity to available resources. Animals that have a “home base” (e.g., nest sites, colonies) must consider distance and energy allocation to optimize foraging efficiency (Alerstam et al 2019). In real estate, property value is often determined by proximity to other properties, and community attributes (e.g., school quality, nearby amenities) can influence a person’s decision to move and purchase a home (Atack and Margo 1998, Feng and Lu 2013).…”

Temporal invariance of social-ecological catchments

“…In ecology, concepts such as central place foraging theory recognize the importance of spatial proximity to available resources. Animals that have a "home base" (e.g., nest sites, colonies) must consider distance and energy allocation to optimize foraging efficiency (Alerstam et al 2019). In real estate, property value is often determined by proximity to other properties, and community attributes (e.g., school quality, nearby amenities) can influence a person's decision to move and purchase a home (Atack andMargo 1998, Feng andLu 2013).…”