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The rook, like all raven and crow species, belongs to the genus of corvids.
In southern Germany, the rook and black carrion crow, also called raven crow, are the most common. Other known representatives are the raven, the magpie and the jackdaw.
The adult rook can be distinguished from the raven crow by its unfeathered, whitish beak base. In the Raven Crow, this is feathered. Young birds lose the feathering at the root of the beak only gradually.
Corvids are omnivores, although in the rook, vegetable components make up more than half of the diet. Insects, snails, small mammals, carrion, eggs found by chance and young of ground nesting birds, but also seeds, sprouts, legumes and berries as well as fruit are on the menu. That songbird populations are noticeably reduced by (rook) crow populations has been disproved by studies. In fact, the ecological impoverishment of gardens poses a much greater threat to songbirds, as they cannot find food or hiding places.
Rook colonies have a "natural maximum size," conditioned by the number of breeding sites and the food supply, beyond which they do not reproduce further. However, if fragmentation occurs, each colony may again grow to its limit. As a result, the total number may multiply.
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The rook was intensively hunted as a supposed agricultural pest (in fact, they are rather beneficial, eating insect pests and mice); in Bavaria, only about 600 of formerly about 19,000 breeding pairs were left in 1955. With the protection of the species in 1977, the population slowly increased again and now stands at 14,284 breeding pairs throughout Bavaria (as of 2020).
As a result of hunting on the one hand and the change to low-structure agricultural landscapes on the other hand, crows have increasingly begun to settle in cities as well. Here they are sufficiently protected and can easily get food. At the same time, they have learned that there is basically no increased danger to them from humans, which is why an approach to less than one meter is possible.
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- ...that crows nest later in life on the type of tree they were born on?
- ...that corvids belong to the songbirds?
Hard to believe, but true: crows fall under the songbirds, even if it may not sound like it at first. However, if you want to immediately label the "singing" as noise, you should remember that even in humans the distinction between noise and song is not always easy...
- ...that crow noise is clearly quieter than normal street noise?
In a study it was proven that crows (64 dB) are quieter than through traffic (69 dB). One of the reasons that there are more complaints about them is that there is little that can be done about traffic-related noise. Also, the habituation effect to road noise is higher, while crows are noisy especially in the breeding season.
- ...that corvids are very intelligent?
They can count, make tools, draw logical conclusions and have a good memory for people. In addition, they are very playful.
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As native birds, all corvids enjoy special protection in principle. They are subject to both the EU Birds Directive and the Federal Nature Conservation Act. While carrion crows may be hunted under the Federal Hunting Act, this does not apply to the rook.
Incidentally, not only the animals themselves are protected, but also their nesting sites. And this is even independent of whether they are currently being used or not.
Exceptions to this can only be granted in individual cases after strict examination by the Higher Nature Conservation Authority - in our case the Government of Upper Bavaria.
During the breeding season (approx. mid-March to mid-June), no disturbing measures are permitted as a matter of principle.
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The rook has been establishing itself in the Rosenheim area since about 2010. Since then, the number of breeding pairs has increased from 45 to 420. The two largest colonies are located along the Mangfall and the Mangfall Canal, as well as at the Loretowiese. In 2020, smaller splinter colonies were added in the north of Rosenheim in the area of Schiller-/Goethe-/Burgfeldstraße.
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Important: any action taken without the permission of the higher nature conservation authority constitutes a criminal offense under §§ 69, 71 of the Federal Nature Conservation Act and will be prosecuted.
Tolerance towards crows
Probably the most effective and also most gentle measure for the animals is: more tolerance. For those affected at the first moment possibly difficult to accept, the proposal deserves closer consideration. As already described, it is still a protected and nationwide rather rare bird species. The fact that it occurs more frequently in Rosenheim should be seen as an opportunity, for example for observations with children. Where necessary, selective measures on the part of the city will continue to be examined. A significant reduction of the animals will not be possible. With the often desired scaring away measures, there is always the danger that, although in the short term there will be fewer animals in one place, in the long term new urban areas will always be repopulated and old nesting sites will also be reactivated. In addition, more emphasis should be placed on environmental education measures to increase acceptance among the population.
Removal of nests / breeding sites
By removing nests or removing branches during the absence of the birds, attempts can be made to prevent reestablishment at the old site. However, this does not prevent new nest construction. At worst, however, this results in fragmentation of existing colonies, which spread to additional areas and increase in population.
Scaring away by sound
Loud noises, calls of birds of prey or warning calls of crows are played at irregular intervals or generated by passing citizens. This is done to make the crows perceive the site as unattractive for settlement. At best, they can be directed to areas with less conflict. However, the experience of other municipalities shows that these measures have to be used for years, are of little use and, at worst, result in the fragmentation of colonies. Above all, the crows quickly learn that there is no danger from the sounds or that no crow is responsible for the warning sounds. In addition, residents must accept a certain amount of noise with this measure.
Scaring away by birds of prey
The targeted use of birds of prey by falconers is intended to reduce the attractiveness of resting and nesting sites and to induce the birds to relocate to quieter and less dangerous areas. Individual crows may be struck to magnify the effect. There are reports from falconers that they are recognized by the crows (by clothing, voice, appearance, even the car used to get there), making the measure ineffective after a very short time. The animals understand the connection between the falconer and the appearance of the bird of prey and consequently that there is no more danger as soon as the falconer is gone again. Again, splinter colonies must be expected.
Shooting / Hunting
The purposeful shooting of animals reduces on the one hand the number of animals, at the same time the current breeding and nesting place becomes unattractive for the animals due to the danger. Shooting is limited to the carrion crow, the rook is protected from shooting. In Rosenheim, mainly the rook is settled, which prohibits shooting. In addition, hunting activities are generally not allowed within inhabited areas.
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- 2019: Due to ash shoot dieback, extensive cutting measures had to be carried out in the forest along the Mangfall. In the process, several breeding trees were felled. As a result, the colony fragmented and there was increased resettlement in Oberwöhr. In addition, the breeding sites shifted closer to the settlement boundary.
- 2020: Birdgards were used for the first time for acoustic deterrence in the Loretowiese area. As a result, the number of breeding pairs decreased from 164 to 63. At the same time, existing colonies probably fragmented during the measures and moved towards the Inn, Stephanskirchen and to the north of the city, where the number of breeding pairs increased from 27 to 80.
- 2021: Once again, scaring measures were carried out using BirdGard. As in the previous year, these were concentrated on the Mangfall landscape conservation area and, for the first time, on the north of Rosenheim.
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The results of the rook census 2021 by the LBV district group Rosenheim as well as the study results of the state parliament project were presented to the environmental committee on 21.07.2021. The results of the LBV can be accessed here . Since the scaring measures have proven to be ineffective and partly even counterproductive (due to the formation of new splinter colonies), it was unanimously decided not to issue a new exemption for scaring measures for the following year.
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The Bavarian state parliament commissioned the development of a concept for rook management. The first interim report was published in 2021. Briefly summarized, it is evident in the municipal area that scaring away measures fragment the colonies and only redistribute conflicts between humans and animals. In fact, it seems most promising to come to terms with colonies and not interfere with existing colonies. (cf. p. 34 ff.).
In the meantime, the second interim report has also been published.
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This and further information on crows can be read on the following pages:
BR documentary "The clever blacks - corvids https://www.br.de/mediathek/video/natur-exclusiv-tier-doku-die-klugen-schwarzen-rabenvoegel-av:5d24b2f89067840013f30fe1
BR fact fox https://www.br.de/nachrichten/bayern/sind-kraehen-schuld-am-singvogelsterben,QhrDIrQ
Bavarian State Office for the Environment https://www.lfu.bayern.de/natur/vogelschutzwarte/saatkraehenmanagement/index.htm
https://www.bestellen.bayern.de/shoplink/lfu_nat_00193.htm
Landesbund für Vogelschutz e.V https://www.lbv.de/ratgeber/naturwissen/konflikte-mit-tieren/mythen-und-fakten-zu-rabenvoegeln/
https://www.lbv.de/ratgeber/naturwissen/konflikte-mit-tieren/saatkraehe-probleme-und-loesung/
LBV Rosenheim https://rosenheim.lbv.de/naturschutz/voegel/saatkraehen/
Nature and Biodiversity Conservation Union Germany https://www.nabu.de/tiere-und-pflanzen/voegel/portraets/rabenkraehe/
https://www.nabu.de/tiere-und-pflanzen/voegel/portraets/saatkraehe/
Arte Re: "Flying garbage collectors: crows in the fight against plastic waste" (especially the first seven minutes) https://www.youtube.com/watch?v=vuv0z6e5HJk