Hazelnuts are a delicious and nutritious snack enjoyed by both humans and wildlife alike.
However, if you’re a hazelnut grower, you may have noticed that your precious crop is being devoured by some uninvited guests. From rodents to birds, there are a variety of creatures that find hazelnuts irresistible.
But how can you tell which critter is responsible for the damage? In this article, we’ll explore the different signs left by various species and help you identify what’s eating your hazelnuts.
So grab a handful of nuts and let’s get cracking!
What Is Eating My Hazelnuts
Rodents are one of the most common culprits when it comes to hazelnut damage. Mice and voles are particularly drawn to young trees with tender bark, and will tunnel around the base of the tree, gnawing at the bark of trunks and roots. This can damage or even girdle small trees, leading to their death.
If you notice smooth, round holes in the side of your hazelnuts with tooth marks running around the inside of the hole, it’s likely that common dormice are to blame. Wood mice, on the other hand, leave tooth marks on the surface of the nut and across the edge of the hole. The hole may be either circular or ragged in shape.
Bank voles create a round hole with tooth marks across the edge, but not on the surface of the nut. Squirrels tend to split the nuts neatly in half, while great spotted woodpeckers break nuts into pieces or leave large, irregular holes.
It’s not just rodents and birds that enjoy hazelnuts – deer, black bears, and even domestic goats have been known to graze on them. Developing buds and catkins also provide protein-rich food for ruffed grouse.
Rodents: The Most Common Culprits
When it comes to hazelnut damage, rodents are the most common culprits. Mice and voles are particularly damaging to young trees with tender bark. They tunnel around the base of the tree and gnaw at the bark of trunks and roots, which can lead to the death of small trees. To prevent this damage, growers have tried a variety of methods, including baiting, bird poling, and keeping grass away from the trunks.
If you suspect that rodents are damaging your hazelnuts, there are a few ways to identify which type of rodent is to blame. Common dormice leave smooth, round holes in the side of the nut with tooth marks running around the inside of the hole. Wood mice leave tooth marks on the surface of the nut and across the edge of the hole, which may be either circular or ragged in shape. Bank voles create a round hole with tooth marks across the edge but not on the surface of the nut. Squirrels tend to split the nuts neatly in half, while great spotted woodpeckers break nuts into pieces or leave large, irregular holes.
It’s important to note that mice activity increases in the fall due to increasing cold weather and acorns. Mice are omnivores and will eat almost anything, including hazelnuts for food. Additionally, their teeth are constantly growing, so they need to chew on items like wood or acorns to wear down their teeth.
Signs Of Rodent Infestation
Rodents are a common pest in hazelnut orchards, and it’s important to identify signs of infestation early to prevent damage to the trees and nuts. One of the most obvious signs of rodent activity is small, paired tooth marks on the nuts, which are left by mice and voles. Squirrels, on the other hand, leave larger bite marks, and rabbits leave even larger bite marks.
If you notice lumps bitten out of the nuts, it’s likely that deer are responsible. As they only have incisor teeth in their lower jaw, tooth marks may only be visible on one side of the nut. Ragged holes in the nuts are a sign of bird activity, while irregular slimy depressions in the stem indicate slug infestation.
If you suspect a rodent infestation, it’s important to take action quickly. Keep hazelnuts, peanuts, cashews, and other nuts in sealed airtight containers to prevent rodents from accessing them. Peanut butter, almond butter, and hazelnut spread should be kept in the refrigerator if there is a rat infestation.
In addition to damaging hazelnuts, rodents can also cause damage to trees by gnawing at the bark of trunks and roots. Look for tunneling around the base of young trees and smooth, round holes with tooth marks around the inside of the hole.
Identifying signs of rodent infestation early can help prevent further damage and protect your hazelnut crop. Regular monitoring and control measures such as traps or bait stations can help keep rodent populations in check.
Preventing Rodent Damage To Hazelnuts
Rodents can cause significant damage to hazelnut trees, particularly young ones with tender bark. To prevent rodent damage, there are several methods that hazelnut growers can try.
One common method is baiting rodents, which involves placing bait stations around the orchard to attract and kill mice and voles. Another method is bird poling, which involves placing poles around the trees to prevent rodents from climbing up and accessing the trees. Keeping the grass around the trunks trimmed and the rows clean can also help to deter rodents.
If mice or voles do damage or girdle a young tree, it may be necessary to cut out the main trunk and let the suckers grow. Hazelnut growers should use suckers from the roots rather than side shoots from the trunk, as side shoots can grow into weak trees. After the new suckers have grown for a while, growers should choose the sturdiest one and train it as a new, young tree. The rest of the saved suckers should be removed.
In addition to these methods, hazelnut growers may also consider using repellents or installing physical barriers, such as tree guards or fencing, to prevent rodents from accessing the trees. It’s important to monitor the orchard regularly for signs of rodent damage and take action promptly to prevent further damage. By implementing these methods, hazelnut growers can protect their trees and ensure a healthy crop.
Birds: A Surprising Hazelnut Thief
While rodents are the most common culprits of hazelnut damage, birds of prey can also be a surprising threat to hazelnut growers. Red-tailed hawks, also known as chicken hawks in some areas, have excellent hunting skills and appetites that can be utilized by growers. These hawks have eight times better eyesight than humans and can see colors in the ultraviolet spectrum. This means that they can easily spot rodent runs, which appear as lighted highway maps from above due to the phosphorescence of mouse and vole urine.
Red-tailed hawks hunt in open spaces, often from a perch on high perches such as tall trees along orchard edges or man-made bird poles. These birds are the most common raptors to use high perches, but other birds of prey such as the red-shouldered hawk, Cooper’s hawk, merlin (pigeon hawk), American kestrel, white-tailed kite, and great horned owl may also intermittently use poles.
The red-tailed hawk’s diet consists of 85% to 90% small rodents such as mice, voles, squirrels, and gophers. However, they also prey on other birds such as crows, jays, and starlings – all of which gobble hazelnuts. Attracting red-tailed hawks to orchards could save growers hundreds of dollars a year in salvaged nuts and trees. Growers have reported seeing hawks using bird poles in their orchards to help with rodent problems, even if they aren’t eating all of the pests.
It’s important to note that while birds of prey can be beneficial to hazelnut growers, they may also cause damage if they become too populous in an area. Therefore, it’s important for growers to maintain a balance between attracting these birds and preventing overpopulation.
Identifying Bird Damage To Hazelnuts
Birds can also cause damage to hazelnuts, and it’s important to identify the specific type of damage to determine which bird is responsible. Great spotted woodpeckers, for example, break nuts into pieces or leave large, irregular holes. Woodpeckers and nuthatches may also jam hazelnuts into crevices in tree bark, so they can hammer them more easily.
If you notice a smooth, round hole in the side of the nut with tooth marks running around the inside of the hole, it’s likely that common dormice are to blame. However, if you see tooth marks on the surface of the nut and across the edge of the hole, it’s more likely that wood mice are responsible. Bank voles create a round hole with tooth marks across the edge, but not on the surface of the nut.
Squirrels tend to split hazelnuts neatly in half, while some birds may leave ragged or irregular holes. It’s important to note that identifying bird damage may not always be straightforward. For example, early instar gypsy moth larvae feeding on hazelnuts can cause round holes similar to those caused by birds.
Keeping Birds Away From Hazelnut Trees
Birds, particularly crows, are another major threat to hazelnut trees. However, it is important to note that most bird species are protected by federal and state laws, such as the Migratory Bird Treaty Act of 1918. Therefore, it is crucial to implement non-lethal control techniques while applying for a depredation permit from your state’s wildlife agency or the state office of USDA-Wildlife Services.
Propane cannons, cracker shells, hawk kites, netting, and Mylar tape are all effective non-lethal techniques to keep birds away from hazelnut trees. Hawk kites are particularly realistic and seem to work well in orchards. Mylar tape glitters and shakes in the wind, which seems to scare birds away as well. However, it is important to understand that all visual and acoustic repellent techniques have limited effectiveness and work best when combined to overwhelm the birds’ senses.
It is crucial to act quickly when bird damage begins as large numbers of birds can appear, and the longer birds use a feeding site, the harder it is to disperse them. Even when the frightening devices are used properly, birds can habituate to them very quickly if they are not accompanied by lethal control. Therefore, it is important to seek professional guidance and obtain necessary permits before resorting to lethal control methods.
In addition to non-lethal control techniques, attracting birds of prey like red-tailed hawks can also be beneficial. Red-tailed hawks are known for their hunting skills and appetites for small rodents like mice and voles, which make up 85% to 90% of their diet. Attracting red-tailed hawks to hazelnut orchards could save growers hundreds of dollars a year in salvaged nuts and trees. High perches like tall trees along orchard edges or man-made bird poles can be used as hunting grounds for red-tailed hawks and other birds of prey. However, it is important to note that even birds of prey are protected by federal and state laws, and it is crucial to seek professional guidance before implementing any attracting techniques.
