page_title: Tawny owl
section_title: Parental behaviour
hierarchical_section_title: Tawny owl / Breeding / Parental behaviour
caption_attribution_description: Digiscoping with Swarovski ATM 80 HD 30 X, Panasonic GX7 + Lumix G 20mm F1.7 ASPH lens (Adapter DCB)
context_page_description: The tawny owl or brown owl is a stocky, medium-sized owl commonly found in woodlands across much of the Palearctic. The tawny owl is a member of the genus Strix, that is also the origin of the family's name under Linnaean taxonomy. Its underparts are pale with dark streaks, and the upperparts are either rufous, brown or grey. Several of the eight recognised subspecies have each of the main colour variations. This nocturnal bird of prey hunts a wide variety of prey species, but usually primarily takes small mammals such as rodents. Tawny owls usually hunt by dropping from a perch to seize their prey, which they typically swallow whole. In more urban areas, its diet includes a higher proportion of birds, while in arid subtropics many invertebrates such as insects are taken. Other important prey can include frogs with other vertebrate prey taken fairly rarely. Vision and well-developed hearing adaptations combined with silent flight aid its night hunting. The tawny owl is capable of catching smaller owls, but is itself vulnerable to larger raptors, like eagle-owls or goshawks.
context_section_description: The female incubates alone, starting with the first egg for 28–29 days typically, and is fed by the male. The female also broods the chicks, feeding them strips of meat for about 2 weeks, after which they may start swallowing mice and such whole. She continues to feed them until they leave the nest, at which point she may resume her hunting but the male may continue to a majority of food capture and may even feed the offspring directly. Larger prey items tend to be more often fed to chicks such as medium-sized birds, young rabbits and moles where available, while the parents themselves usually eat small rodents (i.e. in Wytham and Ythan Valley). Sometimes when the mother feeds their young, separated feathers are sometimes doled out and consumed by them. In France, 4–19 prey deliveries by the male were recorded per night, or 2.5–3 prey per chick nightly. In Belgium, from as little as 0 to 22 prey items were recorded to be delivered per night, on average 3.7 (range 2.3–5.1) prey per chick nightly. Up to 21% of prey deliveries were done in daylight in Wytham whereas in the Netherlands only 2% were during daytime. In one British nest, with three owlets (the oldest being 15–25 days old) each chick received about 88 g (3.1 oz) of food per night while later near fledging, each would get 124 to 141 g (4.4 to 5.0 oz) per night. In an experiment study, broods were both increased and decreased to see if males differed their food deliveries, it was found that the males did change their food delivers as a result of brood increase or decrease, with the decreased broods being fed well while the increased broods were food stressed and showed particular signs of declining condition of the brooding female as she had less food for herself. Instrinic factors were weighed about the condition of parents in a study from Finland, with the female's age being the most significant factors that could be determined. Furthermore, it was found that male condition was the most important factor for female condition, with older males often in better physical condition. Weather conditions were found to be intrinsic with condition of parents in Finland, and further that larger females could breed earlier and more successfully on average. A study of steroid hormones in a selected 51 pairs within Denmark (from a network of 204 nest boxes) were used to measure hormone levels. It was found that testostrone levels were consistently higher in 3 year old birds of both sexes, birds of this age were more productive in all aspects of breeding than younger owls, although it was not clear to what extent higher breeding success to attributable to hormonal levels versus experience. A testing of testosterone levels in owl offspring within Danube-Ipoly National Park in Hungary determined that experienced parents produced nestlings with more testostrone mainly in correlation with mild weather. In poor weather or inexperienced parents the levels were lower. The testostrone levels in the Hungarian study were found to be lowest in poor weather conditions in the last of the owl's broods and most such young usually died during the early nesting period.
  When they are alarmed or required to act in self-defense near the nest, tawny owls of all ages but especially older nestlings up to fledging age, have been recorded to raise feathers and outstretch wings, to their expand size and possible shield itself, also snapping their bills. Despite the tawny owl's reputation as a highly aggressive bird when encroached upon, the parents are usually retiring even when the area of the nest is broached. Passive measures are usually taken first in parental nest defense. The mother owls are often tight sitters, one female sat motionless even as she was physically turned over, while another sat tight but flushed eventually after several human intrusions. Sometimes parents engage in distraction display when attempting to protect their young but less frequently than do long-eared owls. There is much individual variation in aggressiveness of response to disturbance and threats, with a similar occasio
caption: A tawny owl peers from a tree hollow, which is often what they naturally utilize as nest sites
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