Eggs

Kiore

Kiore are likely to behave similarly to other rodents. Rodents may remove eggs from nests and eat them elsewhere. If the eggs are eaten in the nest there will be a few large fragments and several smaller fragments. Droppings may be present and the nest lining is likely to be disturbed as the animal searches for bits it has dropped.

Can be confused with:
It will be difficult to distinguish between ship rat- and kiore-predated nests. Remember, too, that egg remains might have been scavenged.

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Ship Rat

Nests that have been predated by ship rats tend to have disturbed nest linings where rats have sorted through the lining looking for dropped morsels of food. Large fragments of egg shell are left in the nest and sometimes underneath. If chicks are predated, they may be eaten in the nest or removed to a feeding location nearby. Rat faeces are not always left at the nest.

Can be confused with:
Predation of stoats or other rat species. It will be difficult to distinguish between rat species but stoats often leave paired canine tooth puncture marks in prey remains. Remember, too, that egg remains might have been scavenged.

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Norway rat

Nests that have been predated by Norway rats tend to have disturbed nest linings where rats have sorted through the lining looking for dropped morsels of food. Large fragments of egg shell are left in the nest and sometimes underneath. If chicks are predated, they may be eaten in the nest or removed to a feeding location nearby. Faeces are not always left at the nest.

Can be confused with:
Stoats or other rat species leave similar sign. It will be difficult to distinguish between rat species. Stoats often leave paired puncture marks in prey remains where the canines enter. Remember, too, that egg remains might have been scavenged.

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Possum

Possums leave relatively whole but crushed eggshells.  The edges of the shell are pushed inwards. They are suspected of predating on kiwi eggs. One egg had an 80-120 mm hole chewed in the top or side of egg.

Can be confused with:

Rats, but they leave numerous small fragments and jagged edged shells.  Stoats and ferrets, but they tend to create a hole rather than crush the egg and the edge of the hole will be serrated. Remember, too, that egg remains might have been scavenged.

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Pig

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.

Could be confused with:

Remember, too, that egg remains might have been scavenged by other animals.

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Hedgehog

Eggshell fragments have been found in hedgehog droppings and video footage has shown them taking eggs from ground nesting birds in the MacKenzie Basin. This footage also showed that hedgehogs may have a greater impact on eggs than previously thought, because they often break the egg and carefully lick up all the contents without ingesting eggshell fragments .

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

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Cat

Cats will eat bird eggs when they encounter them. They are likely to crush the egg with their mouth, before removing the contents.

Can be confused with:
Predation of other egg predators e.g. stoats, ferrets, weasels, rats and possums. Remember, too, that egg remains might have been scavenged.

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Weasel

Weasels often find eggs difficult to bite into, so will role them to break them. Small stoats will do this as well.

Can be confused with:

Stoats, as they will also roll eggs. Remember, too, that egg remains might have been scavenged.

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Stoat

If a stoat has been disturbed there may be a small hole where the egg has been pierced with its sharp teeth. If the egg is eaten shell fragments will have a serrated edge.

Can be confused with:
Rats, ferret, feral cat, hedgehogs and weasel egg predation. Remember, too, that egg remains might have been scavenged.

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Ferret

Ferrets are poor climbers and therefore only prey on eggs of bird species that nest on the ground or in burrows. Ferret predation of eggs may be similar to predation by stoats with the ferret piercing the egg with its canine teeth. Eventually the ferret will create a large hole and remove the egg contents, and may break the egg shell into several pieces.

Can be confused with:
Stoat or feral cat predation of eggs. Remember, too, that egg remains might have been scavenged.

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Australian magpie

Australian magpies occasionally eat eggs of other bird species.

Can be confused with:

Eggs pecked by magpies may be confused with eggs pecked by other predatory birds. Remember, too, that egg remains might have been scavenged.

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Rook

Rooks will eat the eggs of other bird species, especially of small birds and ground-nesting birds, although little is documented about characteristic signs of the egg predation. Rooks probably peck a hole in the egg.

Can be confused with:

A number of bird species prey on eggs by pecking holes in the shell and eating the contents. Mammals such as rats, stoats and possums tend to push their snouts into an egg, so the broken fragments point inwards but these often remain partially attached to the shell (or shell membrane). Remember, too, that egg remains might have been scavenged.

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