Rook

What does it look like?

Rooks are large black birds, slightly bigger than magpies. Adults have entirely black plumage with a glossy sheen that often appears slightly purple in the light. A distinctive feature of adult rooks is the featherless, greyish-white skin on their face, extending from the base of the beak to the nostrils. Juvenile birds lack this feature and have fully feathered black faces until they mature, usually between 1–2 years of age.

Rooks have long, pointed black beaks, dark brown eyes, and are known for their harsh, rasping “kaah” call. In flight, they can be identified by their slow but steady wingbeats.

These birds nest in large communal groups called rookeries, typically in tall trees such as eucalyptus, pine, or macrocarpa. They have also been recorded nesting in Norfolk pines and Acacia species, such as brush wattles. Rooks may travel up to 10 km from their night-time roosts to forage, although during the breeding season they usually remain within a few kilometres of the rookery.

Their primary diet consists of invertebrates, particularly fly larvae, adult beetles, and beetle larvae such as grass grubs, especially during the warmer months.

Why is it a problem?

Rooks are primarily insect eaters, but when the soil becomes too hard for them to extract their usual invertebrate prey (particularly during summer) they turn to agricultural crops as an alternative food source. This shift in diet can lead to significant damage on farms and in market gardens.

Rooks feed on a wide range of crops, including newly sown cereals, germinating seedlings, ripening lentils, walnuts, acorns, pumpkin seeds, and occasionally potatoes and fruit. They are known to pull young pumpkin and maize plants from the ground to access the seeds and can tear up large areas of pasture while searching for invertebrates.

Crops at particular risk include precision-planted varieties such as maize, peas, and beans, which may require re-sowing due to rook damage. Rooks may also consume seed heads and puncture ripening fruit such as apples and pears with their beaks.

In areas with high rook densities, their foraging can negatively impact soil invertebrate populations. This, in turn, may affect native species that rely on the same invertebrates for food, potentially disrupting local ecosystems.

Rooks will also rip up light soils by pulling out tufts of grass looking for soil invertebrates such as worms and grubs. This can create small cells of damaged groundcover that in light types can begin to erode. The pumice belts that run through Hawke's Bay are particularly prone to erosion. Patches of up to half a hectare can be exposed over a period of time.

Control methods

Rook control requires specialist skills. We use DRC 1339 poison to control rooks. This toxin is a controlled pesticide specifically used for bird control. Rooks are highly susceptible to this toxin while most other bird species have an increased resistance to it.

Under normal conditions, DRC 1339 is not dangerous to sheep, cows, dogs or other mammals. We provide two main forms of rook control - aerial and ground control.

Aerial Control: Every year, we carry out aerial control operations over all known rookeries in the region, targeting nests directly with an effective method. A licensed operator is suspended from a helicopter on a strop, guided by the pilot to each nest. The operator hand-baits the nest with DRC-1339 in a gel paste form. The birds ingest the poison while preening their feathers after returning to the nest.

Ground Control: If rooks are found feeding in large numbers at a regular location, we may carry out ground control. This is done by a licensed operator who first pre-feeds the birds using battered bread bait. Once the rooks consistently feed from the bait line, the operator replaces the pre-feed with bread laced with the toxin DRC-1339.

If you think you’ve seen rooks on your property or a neighbour’s, we want to hear from you. Listen for their harsh “kaah” call and look for large, glossy, purplish-black birds. You’re most likely to spot them in spring and summer, nesting in large pine or gum trees, or feeding in flocks on pastoral land.

Please do not try to control rooks yourself, as this can cause them to scatter and potentially increase their numbers. If you see a group, try to avoid disturbing them.
If possible, note the location and take a photo, then report it to us.

Related links

• Bionet - Consolidated Pest Management Resources
• Rook call sound