Fur, feathers or scales (vertebrate)

Mouse

Birds

Mice may eat small eggs and nestlings but they are not usually considered a major cause of nest predation. However, rock wren populations in alpine environments could be at risk during mouse outbreaks.

Could be confused with:

Nest kill by other predators, including scavenged remains.

Read more about this species

Kiore

Birds

Populations of some seabirds increased after kiore were eradicated from Little Barrier-Hauturu Island. In 2004, the Department of Conservation carried out an operation to eradicate kiore from the 2,800 hectare island. The following breeding season, Cook’s petrels had a 70% breeding success rate compared with 5% in previous years.

Lizards and frogs

Kiore can have a significant impact on lizards but some lizard species are more susceptible to rat predation than others. Kiore colonised a small island in the Mokohinau Group (Hauraki Gulf) during 1977 and caused a dramatic drop in lizard numbers.

Can be confused with:
Predation of other rats, mustelids (stoat, ferret, weasel) and cats. Remember, too, that animal remains might have been scavenged.

Read more about this species

Ship Rat

Birds

Ship rats will kill and eat small birds and nestlings and will scavenge larger dead birds. Typical evidence of rat predation includes flesh stripped from bones and gnawed bones, possibly with tooth marks visible. They will also harass larger birds, including those as large as kereru, until the incubating bird leaves the nest and the rats can eat the eggs or chicks.

Mammals

There is indirect evidence that the ship rat will eat other rat species and also mice. It is uncertain whether ship rats kill mammals or scavenge what they find.

Lizards and frogs

Rat-predated lizards have been recorded and lizards have been found in rat stomach contents.

Can be confused with:
Predation of mustelids (stoat or weasel), possums, cats or other rats. Mustelid kills can show puncture marks from the canine teeth but mustelids often remove and hide their prey. With bird kill, cats often eat the entire body except for large wing and tail feathers, heads and feet; possums tend to only eat the head and breast and leave the rest. Remember, too, that animal remains might have been scavenged.

Read more about this species

Norway rat

Birds

Norway rats will kill birds by biting the back of their necks. The head is often eaten first and the rest of the body later. Flesh tends to be gnawed from bones and feathers will be left.

Lizards and frogs

Norway rats eat lizards and are known to cause lizard population declines.

Can be confused with:
Kill sign of other predators: other rat species, mustelids (stoat, weasel), possums or cats. Mustelid kills can show distinctive canine-teeth puncture marks that would not be seen in a rat kill but mustelids often remove and hide their prey. With bird kill, cats often eat the entire body except for large wing and tail feathers, heads and feet; possums tend to only eat the head and breast and leave the rest. Remember, too, that animal remains might have been scavenged.

Read more about this species

Possum

Birds

Small bird prey remains may include chewed feathers, and regurgitated feather and bone remains.  Eggshell and other material are sometimes chewed into a 'pellet' that is coughed up. Birds and nestlings often are only partially eaten, favoured areas being the head and chest, with wing and rear being less favoured.

Mammals

Possums are known to scavenge on deer and pig carcasses and are often caught in traps baited with rabbit meat to catch ferrets or stoats.  Scavenging carcasses is thought to be one way that bovine TB is spread between animals.

Lizard and frogs: 

Possums are opportunistic feeders and possibly may eat lizards and frogs if they can catch them but there are no confirmed records of this occurring..

Can be confused with:

The messy feeding sign can be confused with that of ship rat or other rodents, and mustelids like stoats. A key differentiator may be the presence or absence of feather and bone or eggshell 'pellets' produced by possums.  Stoats often kill with a distinctive bite mark to the back of the head and prefer to drag their prey under cover. Remember, too, that animal remains might have been scavenged.

Read more about this species

Pig

Birds

In New Zealand, feral pigs have been known to eat ground-nesting birds and their eggs. However, there is little information available regarding characteristic signs that pigs might leave at nests they have preyed on. There are stories that pigs turn kiwi-skins inside out, but it is not clear if the pig killed the kiwi or ate it after it was found dead.

Mammals

In New Zealand, feral pigs have been known to eat mice, rats, young rabbits, possum carrion, and new-born lambs. Lamb predation has very tell tale signs of skins turned inside out with just the hocks and skins remaining , but there is little information available regarding characteristic signs pigs might leave behind for other species.

Lizards and frogs

Feral pigs are known to eat lizards and frogs. There is little information available regarding characteristic signs pigs might leave behind when they devour lizards and frogs. However, it is likely given their small size that they are often eaten whole.

Could be confused with:

Remember that animal remains might have been scavenged by other animals.

Read more about this species

Hedgehog

Birds

Hedgehogs are known to eat chicks of ground nesting birds, and are known to be significant predators of the eggs and nests of ground nesting birds inhabiting braided rivers in the South Island. They will also attack birds brooding on nest on the ground. Feathers have been found in hedgehog stomachs and dropping .

Mammals

Hedgehogs are known to eat mice. Mouse fur has been found in hedgehog stomachs and droppings . They can also scavenge carcasses such as rabbit and sheep.

Lizards and frogs

Lizard and frog parts have been found in hedgehog droppings and intestines. One study found that more than 20% of hedgehogs had skink remains in their stomach, and this included at least 43 individual skinks . While native lizards appear to be of lesser importance as food than invertebrates, small, localised populations of lizards may still be threatened by hedgehog predation, and large numbers of hedgehogs can have a high impact on native reptile populations .

Can be confused with:
Other predators such as stoats, weasels, cats and rats. Remember, too, that animal remains might have been scavenged.

Read more about this species

Cat

Birds

Small birds are entirely eaten except for some body, wing and tail feathers. More parts of larger birds are left including more body feathers, the tail, wing tips, feet and bill. The pattern of cat predation on freshly killed larger birds can sometimes be distinguished from other predators by the pattern of bite marks. Cats often make the kill by biting into the back of the head. The brain is often eaten first and, sometimes with smaller birds, the whole skull is eaten except for the bill. There may be some crushing of the skull and sternum.

Mammal

Rodents and young rabbits are usually entirely eaten, except sometimes for the tail and pieces of skin. The remains of older rabbits, or large rats, often include stomach and skin turned inside out over the animal’s head.

Lizards and frogs

Lizards are usually eaten entirely. Domestic cats will play with lizards and may have puncture marks in the abdomen area. Frogs and fish are sometimes caught.

Can be confused with:
Other predators such as stoats, ferrets, weasels, and possums. With bird kill, all these predators will on occasion leave half-eaten carcasses or a scattering of feathers. Remember, too, that animal remains might have been scavenged.

Read more about this species

Weasel

Weasel droppings can give kill information as they often contain remnants of feather, fur, bones and insect cuticle.

Birds

There are few observations of weasel kills in New Zealand, although they are known to kill small forest birds such as rifleman. Observations from overseas suggest that, like the stoat, they often kill with a bite to the neck or back of the head.

Mammals

Weasels kill mice (their preferred food) and juvenile rabbits with a bite to back of the neck or skull.  They will follow mice down into their burrows.

Lizards and frogs

Weasels often eat skinks and geckos. Lizard remains are often obvious if dropping are teased apart.

Can be confused with:

Stoats, which prey in a similar manner, and have droppings that similarly show remnants of small prey. Remember, too, that animal remains might have been scavenged.

Read more about this species

Stoat

Stoat droppings can give kill information as they often contain remnants of feather, fur, bones and insect cuticle.

Birds

Stoats kill prey with a distinctive bite to the back of the neck. Typically stoats move prey to their dens or to nearby cover, seldom leaving prey items in the open, unless the prey it too large to drag. Messy remains such as smashed egg shells, chewed remains, and disturbed bird nest lining make it more likely to be the work of rats. The inter-canine distance of a stoat is approximately 6.4 mm and sometimes puncture wounds can be found on the neck or head of birds, but these are difficult to discern from ferrets and feral cats. Droppings may contain remnants of feather, fur, bones and insect cuticle.

Mammals

Stoats kill other small mammals such as mice, rats and rabbits with a distinctive bite to the back of the neck and often remove the animal to their den. Rabbits may let out a shrill cry when attacked by stoats.

Lizards and frogs

Stoats will generally eat a whole lizard, although feet and pieces of tail may be left behind.

Can be confused with:
Kill sign of rats, feral cat and ferrets; also weasels in the case of small mammals; and hedgehogs and weasels in the case of lizards and frogs. Weasel droppings similarly show remnants of prey. Remember, too, that animal remains might have been scavenged.

Read more about this species

Ferret

Ferret droppings can give kill information as they often contain remnants of feather, fur, bones and insect cuticle.

Birds

Like other mustelids, ferrets kill birds with a distinctive bite to the back of the neck. Typically, ferrets will move their prey to cover, seldom leaving prey items in the open. Sometimes puncture wounds can be found on the neck or head of birds, but these are difficult to discern from stoats and feral cats. The average inter-canine distance of a ferret is approximately 10.7 mm.

Mammals

Ferrets kill other small mammals with a distinctive bite to the back of their neck. In New Zealand, ferrets eat rabbits all year round, but can also eat mice and rats. Ferrets are not strong runners, and therefore hunt rabbits in their burrows. Ferrets use their senses to track lactating female rabbits back to burrows full of nestling young. Ferrets can create and scent-mark caches of surplus food.

Lizards and frogs

Ferrets prey on lizards and frogs, and are likely to eat them whole, leaving few remains. Lizard scales, feet and tail parts will be obvious if ferret droppings are partitioned under a microscope.

Can be confused with:

Predation by cats, stoats and weasels. Remember, too, that animal remains might have been scavenged.

Read more about this species

Australian magpie

Birds

Magpies occasionally prey on small birds. Little is known about what evidence they might leave in the way of a corpse or feathers but remains may be seen in pellets ejected from the mouth.

Mammal

Magpies occasionally prey on mice or feed on carrion. The remains may be seen in ejected pellets.

Lizard and frogs

Magpies occasionally prey on lizards or frogs. The remains may be seen in ejected pellets.

Can be confused with:

Kill by pther predators and with pellets ejected by other bird species (such as morepork, falcon, Australasian harrier, rook, and kingfisher). Remember, too, that animal remains might have been scavenged.

Read more about this species

Rook

Birds

Rooks may eat nestlings of other bird species, especially small birds and ground-nesting birds. No information could be found to describe what rook predation looks like or how it differs from other predators.

Mammal

Rooks may also eat small mammals, such as mice and may feed on already dead larger mammals. No information could be found to describe what rook predation or mammal feeding sign looks like or how it differs from other predators. Small mammals, such as mice, are probably swallowed whole, so it is unlikely that evidence is left behind. 

Lizards and frogs

Rooks can eat lizards and frogs. Not much field sign will be found because these species would be swallowed whole.

Note: some regurgitated bones may be present in rook crop castings.

Can be confused with:

Predation of other predatory and omnivorous birds, including pellets that other bird species regurgitate. Beak pecking marks on animal remains killed by larger prey or carrion could be hard to attribute to a specific bird species. Mammal predation is usually different to that caused by birds. Remember, too, that animal remains might have been scavenged.

Read more about this species