T.E.R:R.A.I.N - Taranaki Educational Resource: Research, Analysis and Information Network


Rook (Corvus frugilegus)

Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Passeriformes
Family: Corvidae
Genus: Corvus
Species: C. frugilegus
Binomial name: Corvus frugilegus
Common names: Rook, Crow

The rook (Corvus frugilegus) is a member of the family Corvidae in the passerine order of birds and are residents in Great Britain, Ireland and much of north and central Europe. It is the only member of the crow family found in New Zealand. Rooks were introduced by Acclimatisation Societies in 1862-74 to control insects and remind settlers of home. They now naturalised in New Zealand and were widespread through out New Zealand but their existing numbers are not known due the nomadic nature of the remaining rooks.

Rooks are now listed as an Unwanted Organism in New Zealand because it is an invasive pest and many regional councils are actively eradicating them. Rooks are a threat to cropping and horticulture, although they do play a role in controlling insect pests as almost 75% of their diet is insects. When they target alternative food sources, flocks of several hundred rooks are capable of wiping out a crop in a few days. Before their numbers were reduced, they were a serious problem to germinating arable crops such as maize, sweet corn, cereals, pumpkins, peas (both at planting and maturing), and apples. Rooks can also damage pasture by opening it up to thistles and other weeds while looking for grass grub. On the positive side they do remove a number of pest insects and break up stock dung looking for fly larvae. Rooks also impact the native bird populations as they harass native birds and restrict their range. They also kill and eat small birds, their eggs and their young. Lizards and native insects are also on their diet.

Rooks have a wingspan of 30 cm and a length of >47 cm. They are almost entirely black with a purplish gloss. The face is bare light grey skin, the beak is long, pointed and black, and the eye is dark brown. The legs and feet are generally black and the bill grey-black. When walking on the ground they have the appearance of baggy-trouser like feathers on the upper leg.

Rooks like nesting in the tops of very tall trees. Twigs, leaves, and pine needles are used to build their nests which are usually lined with wool and grass. Rooks often nest within metres of each other, in groups called rookeries. The largest rookery in New Zealand was nearly 1,000 nests but these massive groupings are a thing of the pass. Egg-laying is from late August to late October. Clutches typically consist of 1-4 and sometimes as many as seven eggs. The eggs are pale greenish blue with brown splotches (39 x 28 mm, 16 g). Females alone incubate the eggs (15-19 days) and broods the nestlings. The male feeds the female and nestlings, which fledge at between 26 and 38 days. Generally rooks start to breed at between 2-3 years of age. The longest living banded rook in Hawke’s Bay was about 15 years.
When nests are located a helicopter may be used to apply poison to the nest, eggs or chicks.

The difference between a rook and two other common black feathered birds.



  



Rookery

Rooks nest.
 

Thanks to Wikipedia for text and information     https://creativecommons.org/licenses/by-sa/3.0/