Ronny Steen

Ronny Steen
Norwegian University of Life Sciences · Department of Ecology and Natural Resource Management (INA)

PhD in Ecology

About

44
Publications
158,295
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562
Citations
Introduction
Working experience: Ecological field research Teaching in ecology and zoology Background: PhD from Norwegian University of Life Sciences, 2010. Thesis: Food provisioning in a generalist predator: selecting, preparing, allocating and feeding prey to nestlings in the Eurasian kestrel (Falco tinnunculus).
Additional affiliations
August 2006 - present
Norwegian University of Life Sciences
Education
August 2006 - October 2010

Publications

Publications (44)
Article
Full-text available
The feeding constraint hypothesis states that an inability of young nestlings to ingest prey included in the diet of older nestlings and adult birds affects the evolution of parental behaviour, and predicts that the extent of prey preparation would increase with prey size and decrease with nestling age. In the Eurasian kestrel, Falco tinnunculus, a...
Article
Full-text available
In altricial birds, parents are assumed to optimize the total food delivery to the brood given the time constraints set by self-feeding and food collecting. Older nestlings may require more food than younger ones, and nestlings may need more energy when their growth rate is higher. By video monitoring prey deliveries in ten nests of the Eurasian Ke...
Article
Full-text available
Raptors are known for asymmetric parental roles, with the female brooding and feeding offspring, and the male providing food, usually assisted by the female from the latter part of the rearing period. Yet, the evolution of this role asymmetry is poorly understood. From filming prey delivery and handling in 61 nests of 9 raptor species, we show that...
Technical Report
Full-text available
A short movie about our fieldwork on the Eleonora's falcon in Greece. Download pdf to activate the link to the video, or go directly to https://vimeo.com/113836644.
Article
Data collection on interactions between organisms and their environment has traditionally been conducted by on‐site human observations, a time‐consuming enterprise that could explain the shortage of around‐the‐clock observations of free‐ranging wild animals. In this paper, I outline a time‐efficient procedure to collect data on flower‐visiting anim...
Article
Full-text available
Birds nesting on riverine beaches are exposed to large temperature fluctuations, while changing water levels pose flooding risks. We used miniature temperature loggers ( i Buttons®) placed in nests and on the beach surface combined with time‐lapse photography to study incubation behaviour in the black skimmer ( Rynchops niger ) on the Manu River, P...
Article
Full-text available
According to the alternative prey hypothesis (APH), the temporal synchrony in population fluctuations of microtine rodents and other small herbivores in boreal areas is caused by generalist predators with numerical and functional response to microtines, leading to an increased predation of prey alternative to microtines in the low phase of the micr...
Article
Premise: Capparis spinosa is a widespread charismatic plant, in which the nocturnal floral habit contrasts with the high visitation by diurnal bees and the pronounced scarcity of hawkmoths. To resolve this discrepancy and elucidate floral evolution of C. spinosa, we analyzed the intrafloral patterns of visual and olfactory cues in relation to the...
Article
Animals display a range of diurnal and nocturnal activity patterns and, among mammals, a high proportion of species are crepuscular or nocturnal. Daily activities are often endogenous and oscillate on a light:dark regime. Such cycles are referred to as ‘circadian’ and are generally influenced by biotic and abiotic factors. I investigated the daily...
Article
La frecuencia de aleteo es un parámetro muy importante cuando se estudia el rendimiento del vuelo en colibríes. El revoloteo de los colibríes durante la extracción de néctar influye en la eficiencia para conseguir alimento, lo que a su vez influencia en su éxito de supervivencia y de reproducción. Por lo tanto, el revoloteo constituye una parte imp...
Article
Birds providing prey with a clumped distribution often return to the previous capture site after having delivered a prey item at the nest. However, details of this foraging tactic are still poorly known, in particular for birds of prey, which often travel far from their nest. We radio-tracked four provisioning male Boreal Owls (Aegolius funereus) d...
Article
Full-text available
In the family Orchidaceae, many species have highly specialised floral structures and floral fragrances resulting from interactions with specific pollinators. Olfactory cues are important for the moths to locate orchids at a distance, whereas visual cues are important at a closer range. In this study, we combined a portable air entrainment kit with...
Article
Full-text available
Nine species of carabid beetles (Coleoptera, Carabidae) were pitfall-trapped during two years in an alpine glacier foreland of southern Norway. A two-year (biennial) life cycle was documented for Nebria nivalis (Paykull, 1790), N. rufescens (Ström, 1768), and Patrobus septentrionis Dejean, 1828. This was based on the simultaneous hibernation of lar...
Article
Full-text available
Crossbills Loxia spp. breed during late winter and early spring and feed their nestlings almost exclusively with seeds from conifer cones. In the present paper, we studied a breeding pair of Parrot Crossbills Loxia pytyopsittacus from dawn to dusk in Southern Norway using a time-lapse camera. The study was conducted in the second half of the nestli...
Article
Full-text available
Animals are adapted to a range of activity patterns, from diurnal to nocturnal. Under normal conditions, the 24-hour rhythm is entrained by changes in light intensity during twilight, i.e. the light and dark cycle. Many rodent species exhibit predator avoidance by adjusting their activity in relation to space or time, which is weighed against the n...
Data
Full-text available
Article
Capsule: Automated monitoring of daily activity in birds can be facilitated by the use of a smartphone with video analysis software. Aims: To test the application of an iPhone 5 smartphone with video motion detection for monitoring birds remotely, transferring the data over a mobile network and extracting the data automatically. Methods: A customiz...
Data
Full-text available
onlinelibrary.wiley.com/doi/10.1111/2041-210X.12654/full The use of a compact (Point-and-Shot) camera to automatically detect events. The system consist of a off-the shelf Canon PowerShot camera and CHDK script enabling motion detection. As a model species a Creeping thistle flower was monitored to register honeybee visits (frequency and duration)....
Article
Long-term studies of subtidal marine animals in the wild are a demanding enterprise. Traditionally, data collection has been limited to direct observations during SCUBA diving. In the past decade, video technology has improved rapidly and behavioural monitoring of marine organisms has successfully been conducted by using modern video-recording equi...
Article
Full-text available
Raptors deviate from the norm among provisioning birds by having asymmetric parental roles, with the female brooding and feeding offspring, and the male providing food, assisted by the female from the latter part of the rearing period. To investigate the poorly understood evolution of role asymmetry in raptors at an intraspecific level, we videorec...
Article
Full-text available
Wingbeat frequency is an important parameter when studying flight performance in hummingbirds and could be put into an ecological and evolutionary context to investigate the decisions that a hummingbird takes regarding foraging efficiency. Previous studies of wingbeat frequencies in hummingbirds have been undertaken with captive birds, most probabl...
Article
Full-text available
Long-term studies of subtidal marine animals in the wild are a demanding enterprise. Traditionally, data collection has been limited to direct observations during SCUBA diving. In the past decade, video technology has improved rapidly and behavioural monitoring of marine organisms has successfully been conducted by using modern video-recording equi...
Article
Full-text available
Dead sporocarps contribute to forest biodiversity by supporting a specialised decomposer fauna. However, detailed succession studies are few and microarthropods are rarely included. In a spruce-dominated forest reserve near Oslo in southern Norway, sporocarps of Fomitopsis pinicola with known age since death (0-5 years) were sampled and invertebrat...
Article
Full-text available
In the Orchidaceae family, many species have a highly specialized floral structure and floral fragrance due to interactions with specific pollinators. Pollinators foraging on orchids have traditionally been monitored by detecting pollen vectors on insects, recording tracks from the moths on the orchids, and by direct observations. In the present st...
Article
Full-text available
In birds with bi-parental care, the provisioning link between prey capture and delivery to dependent offspring is regarded as often symmetric between the mates. However, in raptors, the larger female usually broods and feeds the nestlings, while the smaller male provides food for the family, assisted by the female in the latter part of the nestling...
Article
Full-text available
Small mammals with leucism are very rarely recorded, most likely because the probability of surviving to maturity would be very low for abnormal, white individuals. Here we report a record of a bank vole (Myodes glareolus) with complete leucism delivered to a nest of the Eurasian kestrel (Falco tinnunculus) in the boreal forest in SE Norway.
Article
Documenting species interactions is a time consuming enterprise, in particular for rare interaction events and interactions taking place at night. Pollinators foraging on orchids have traditionally been monitored by discovering pollen vectors on collected insects, recording traces left by moths on the orchid, direct observations and recently by con...
Article
Full-text available
In this study we used a portable event-triggered video surveillance system for monitoring flower-visiting bumblebees. The system consist of mini digital recorder (mini-DVR) with a video motion detection (VMD) sensor which detects changes in the image captured by the camera, the intruder triggers the recording immediately. The sensitivity and the de...
Article
Full-text available
In altricial birds the type of prey selected by parents for their nestlings may affect the allocation of time and energy spent on hunting, preparing prey and feeding the nestlings, which in turn may affect the rate of provisioning. Raptors take relatively large prey items, which facilitates the quantification of rates of prey items and prey mass de...
Article
Full-text available
Recent development in video monitoring has allowed collecting of data on prey deliveries at raptor nests, and this offers an opportunity to relate prey selection to short-term changes in environmental factors on a scale of hours. Whereas raptors may specialize on ectothermic prey at southern latitudes, only some generalist raptors may include such...
Article
Full-text available
Los sistemas de vigilancia por video desarrollados recientemente permiten registrar variables como la detección del movimiento. En este estudio, describo el uso de un sistema de vigilancia con video portátil para analizar las entregas de presas en cajas nido usadas por Falco tinnunculus. El sistema consistió en un mini DVR con detección de movimien...
Article
Full-text available
In Norway, a positive relationship between spring numbers of lesser spotted woodpecker (Dendrocopos minor) and previous June temperatures has been interpreted as an effect of temperatures on woodpecker survival and reproduction during the breeding season. This article considers the possibility that woodpecker numbers are related to the abundance of...
Article
Full-text available
During the past decades, goshawk (Accipiter gentilis) populations have declined in forest-dominated landscapes in Norway. To reveal the importance of different prey species in forest versus farmland landscapes, we video recorded 146 prey deliveries at four nests in a farmland-dominated area and three nests in a forest-dominated area in south-easter...
Article
Full-text available
Weather may play an important role in population dynamics by effects on breeding success and survival. To establish the impact of weather on populations of Lesser Spotted Woodpecker Dendrocopos minor we compared numbers in two regions in Norway with relevant temperature data. During 1990 to 2002 observed spring numbers varied from 1 to 52 in the we...

Questions

Questions (41)
Question
For many camera trap studies it is a problem that it is not possible to distinguish individuals, therefore consecutive visits may be the same individual. Either an individual triggers a burst of captures during one visit, or the individual moves consecutively in an out of the camera view during a short time period.
To minimize double counting many studies are using a time gap (hit window), which is the length of time used to group consecutive images/videos together as single detections (given that the data are from the same camera and featuring the same species). This will vary between study designs, for example bait site will cause individuals to stay within the detections zone for a longer period compared to non-baited sites. Further, some species will be more likely to stay at the site than others.
Is there a good procedure to estimate an optimal time gap (hit window) for an existing data set?
Best regards,
Ronny
Question
I wonder if randomized and controlled studies exist for the following triplet therapies in Multiple Myeloma:
1) "Daratumumab, pomalidomide and dexamethasone"
2) "Carfilzomib, pomalidomide, and dexamethasone"
Regards,
Ronny
Question
I'm about to analyse habitat selection in a owl inhabiting coastal and maritime heath habitats. I have GPS-positions and want to check if the owl are more likely to stay at elevations in the terrain. I have digital elevation models (DEM) for the area and want to calculate habitat openness. I tried Package 'horizon' - cran.r, but got some strange results. Anyone that could help calculating habitat openness from a digital elevation models (DEM)?

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