Bringing a Time–Depth Perspective to Collective Animal Behaviour

The field of collective animal behaviour examines how relatively simple, local interactions between individuals in groups combine to produce global-level outcomes. Existing mathematical models and empirical work have identified candidate mechanisms for numerous collective phenomena but have typically focused on one-off or short-term performance. We argue that feedback between collective performance and learning – giving the former the capacity to become an adaptive, and potentially cumulative, process – is a currently poorly explored but crucial mechanism in understanding collective systems. We synthesise material ranging from swarm intelligence in social insects through collective movements in vertebrates to collective decision making in animal and human groups, to propose avenues for future research to identify the potential for changes in these systems to accumulate over time

Fine-scale changes in flight effort revealed by animal-borne loggers

The movements of the air are central to the life of flying birds, because they can determine whether the costs of flight are closer to resting or sprinting, and whether birds are able to reach their destination. Yet for species relying mainly on flapping flight, studies about the effects of weather on flight effort have mainly focussed on wind, with other atmospheric factors receiving less attention. In addition, with the development of new technologies to measure flight effort, it has become clear that some methods need standardisation and further verification. The goal of this PhD is to provide insight into how atmospheric conditions affect flight costs more broadly and study the extent to which birds prioritise energy expenditure over other currencies, such as time and risk. I used high-frequency data-loggers to explore the combined effects of wind and thermals, as well as air density, on flight effort over fine scales, as well as how birds adjust their behaviour to these factors. Results showed that pigeons (Columba livia), which are not limited by energy expenditure, prioritise speed over energy savings, and use a very costly flight style which could serve as a predator-avoidance strategy. I also found that wind support was a strong predictor of whether chick-rearing tropicbirds (Phaethon rubricauda) use thermal soaring to save energy during foraging trips, suggesting that birds were weighing up the trade-off between energy and time, and chose to save energy only when this would not cost them too much time. Comparison of air density between seasons also revealed that the flapping flight of tropicbirds was more costly during summer, when air density was lower. This finding shows that the effect of seasonal changes in air density on flight costs is significant, outweighing the influence of both wind and thermal availability. It also sheds new light on how flight costs (particularly those in tropical birds) might be affected by global change. Finally, the analysis of the accelerometer data showed that the type of tag used, as well as differences in the longitudinal position and attachment method, affected the amplitude of the signal, which has implications for the robustness of acceleration-based proxies for flight effort. Nonetheless, the adoption of standardized calibrations should facilitate the comparison of these metrics between study sites and through time, improving the prospect that they can be used to study the effect of a changing climate on flight costs and avian ecology

The implications of costly airflows for space-use and movement decisions in birds

The behavioural ecology of flight has largely considered how birds respond to mean flow conditions, but it is the gusty or extreme airflows that are likely to be particularly challenging. This thesis addresses this, examining the strategies birds use to negotiate turbulence over land, and exceedingly strong winds at sea. I first develop a method for sensing turbulence at fine scales using data collected onboard the animals themselves, taking homing pigeons (Columba livia) as model flapping fliers. Fine scale variation in the flight altitude and body displacement emerged as effective proxies of turbulence. I then assess the impact of freestream turbulence on flapping fliers and find that pigeons adapted their wingbeat kinematics (frequency and amplitude) to increase their flight stability in response to turbulence, but did so without a clear increase in flight effort. In my final two chapters I examine the responses of two seabird species to strong winds, first at sea, and then on land. Specifically, I investigate how streaked shearwaters (Calonectris leucomelas) respond to tropical cyclones, and how common guillemots (Uria aalge) select their breeding cliffs in relation to airflow conditions. I find that shearwaters fly towards the eye of the storm. This tendency increases with cyclone intensity and may enable birds to avoid strong onshore winds and reduce the associated risks of forced landings and/ or injury. Finally, computational fluid dynamics models reveal that guillemots select breeding cliffs that are sheltered from wind and storm conditions, rather than from the mean wind alone, or heat stress. This model of habitat selection could also predict habitat use across islands. Overall, this highlights the varied and sometimes surprising capacities of birds to cope with extreme and variable airflows and operate in areas that are, as yet, inaccessible to aircraft

Visually guided flight in birds using the budgerigar (Melopsittacus undulatus) as a model system

Keywords: Edge detection, Optic flow, Obstacle avoidanc

Hunting tactics of Peregrines and other falcons

De slechtvalk was bijna uitgestorven door giftige residu’s van landbouwchemicaliën, maar de stand heeft zich hersteld. Dekker deed onderzoek naar de invloed van de terugkeer van deze roofvogel op zijn prooisoorten in Nederland en Canada. Hij heeft gegevens verzameld van 44 jaar, in alle seizoenen en in acht verschillende Canadese landschappen, alsmede aan de Friese waddenkust. In totaal zag hij slechtvalken 470 prooien slaan. Daarvan bestond 85 procent uit watervogels. Daarnaast werden er 104 prooien gepakt door drie andere valkensoorten uit deze studie: het smelleken, de giervalk en de prairievalk. Het jachtsucces van trekkende of overwinterende slechtvalken varieerde van zeven tot twaalf procent

The release of common pheasants and grey partridges for pointing dog training- consequences for biodiversity, animal welfare and health -Scientific Opinion of the Panel on biodiversity of the Norwegian Scientific Committee for Food and Environment

Source at https://vkm.no/

The release of common pheasants and grey partridges for pointing dog training- consequences for biodiversity, animal welfare and health. Scientific Opinion of the Panel on Biodiversity of the Norwegian Scientific Committee for Food and Environment

Source at https://vkm.no/.Bakgrunn Siden sent på 1800-tallet har det blitt satt ut et ukjent antall tamme fasaner og rapphøns i norsk natur. Disse fuglene brukes til jakttrening av stående fuglehunder. Import, hold og utsetting av fasaner og rapphøns har i liten grad vært regulert og det er heller ikke utredet hvilke konsekvenser som import, hold og utsetting og jakttrening vil kunne ha for biologisk mangfold, dyrehelse og dyrevelferd. Miljødirektoratet og Mattilsynet har i felleskap bedt VKM om å utarbeide en vitenskapelig vurdering av mulige konsekvenser av utsetting av fasan og rapphøns på biologisk mangfold, dyrehelse og dyrevelferd. VKM ble også bedt om å foreslå eventuelle risikoreduserende tiltak for biologisk mangfold og dyrevelferd. Metoder VKM opprettet en prosjektgruppe med ekspertise innenfor blant annet fugleøkologi, landskapsøkologi, populasjonsbiologi, viltmedisin og dyrevelferd. Gruppen utførte systematiske litteratursøk, undersøkte resultatene fra søkene og supplerte med andre relevante studier der det var nødvendig. I mangel av studier fra norske forhold brukte VKM studier fra andre land som setter ut fasaner og rapphøns (og i noen tilfeller andre arter av fuglevilt) som referanse. VKM undersøkte observasjonsdata for fasaner og rapphøns i Norge for perioden 2000 til 2022. I vurderingen av de ulike aspektene som vil kunne påvirkes av utsettingen, la VKM til grunn en årlig utsetting av noen få tusen fugler i Norge. Høyere antall og tetthet av fugler vil øke sannsynligheten for negative effekter og alvorlighetsgraden av konsekvensene. VKM vurderte effekten som utsatte fasaner og rapphøns har på konkurranse med norske fugler,, krysning med beslektede arter, sykdomsoverføring, effekter på flora (herbivori), og fauna (predasjon). I tillegg ble indirekte effekter gjennom interaksjon med andre arter vurtdert. VKM vurderte også effekt på biologisk mangfold i et 50-års perspektiv. I tillegg diskuterte VKM hvordan fuglenes velferd vil kunne påvirkes av hold, transport, utsetting, og eksponering for jakthunder. VKM lister også opp relevante sykdommer og vurderer den potensielle effekten av disse på dyrehelse under hold, transport og utsetting. For vurdering av aspekter relatert til import og dyrehelse, la VKM til grunn at fuglene importeres fra Sverige. Resultater og konklusjoner VKMs vurderinger viste at utsetting av fasaner og rapphøns i norsk natur medfører risiko for biologisk mangfold, dyrehelse og dyrevelferd. Risiko for økt konkurranse om mat vinterstid med fugler som har lignende økologisk nisje som fasaner og rapphøns, er lav på nasjonal skala og moderat på lokal skala. Det gjelder spesielt gulspurv, Emberiza citronella. Denne arten er klassifisert som sårbar på den nasjonale rødlisten grunnet økende nedgang i bestanden, som igjen er forårsaket av redusert tilgjengelighet av mat om vinteren. Det er videre moderat risiko for predasjon på invertebrater (virvelløse dyr) og negative effekter på flora.The release of common pheasants and grey partridges for pointing dog training- consequences for biodiversity, animal welfare and health. Scientific Opinion of the Panel on Biodiversity of the Norwegian Scientific Committee for Food and EnvironmentpublishedVersio