Autumn Stockpiles

 Autumn Stockpiles

Red Headed Woodpecker with acorn, Myrtle Beach Oct 2019.

Autumn is an interesting time to observe birds and wildlife. In many parts of temperate North America and Europe, autumn means that winter is around the corner. During this time, birds and certain insect species migrate, while some animals like bears, marmots, and certain mice prepare to hibernate. Food is often scarce during the winter months, and even in a mild region like Southeastern North Carolina, birds and animals need a consistent source of food when plants go dormant and insects go into hibernation. Some species of bird and mammals will stockpile food for later use. While it is a common belief that animals store up food for the winter, many birds and mammals will stockpile food throughout the year for various reasons. This behaivor is known as hoarding or caching and is a survival technique to ensure food availability during lean times like frigid winters, extended droughts, rainy weather, or another event that causes food scarcity. Squirrels, mice/rats, crows, jays, shrikes, certain woodpeckers, and small woodland birds are examples of animals that routinely hoard food for later use. 

Hoarding 

White Oak acorn collected on walk around Greenfield Lake

Hoarding or caching is the behaivor of storing or hiding food in deliberate spots for later use. It can serve many purposes in the natural world although the most common reason is to ensure that food is available in times of scarcity. Animals also use this technique to hide precious food sources from other members of their species or from other species and possibly as a  means of ripening nuts or berries. Ants, bees, wasps, and other insects may also store food although this behaivor is different from the food hoarding seen with birds or rodents. Hoarding is most common in the autumn and winter although many birds will save up food throughout the year. Chipmunks, rats, and hamsters stockpile large amounts of food in their dens or in sites called larders. Certain birds like Acorn and Red Headed Woodpeckers will also store their food in a handful of places. Most other birds and mammals store individual items in scattered locations across the landscape. Both techniques have their advantages and disadvantages. Food larders are easy for a bird or rodent to defend but a raid or disaster could wipe out an entire food supply. Food stockpiled in this way tends to be kept for long periods of time (months or longer) and most birds that stockpile food in this way are colonial (as is the case with Red Headed and Acorn Woodpeckers). Scattered sites do not have to be defended as much as most items are well-hidden in unique locations and the loss of a few sites will not jeopardize the food supply. However, animals are more likely to forget items. Most of the birds and all squirrels in our area stockpile food in scattered locations rather than in a single location. Nuts and seeds are better candidates for long-term storage than fruits, or insect prey. Nuts and acorns may still be edible months after they are hidden, while meat or fruits could spoil if they are not retrieved in a timely manner. Warmer temperatures during the winter can cause food items to spoil according to this video about Grey Jays from Cornell Lab of Ornithology.

Learn more about hoarding and caching by visiting its article on Wikipedia. This is a good place to start and there are additional references that editors used on the bottom of each Wikipedia article. 

Animals that Cache Food 

In the Cape Fear Region there are a number of birds and mammals that store food for later use. All three of the squirrel species in our area store nuts and seeds during the autumn with Grey and Fox Squirrel using the scatter hoarding technique. In the interior of the Carolinas, the Eastern Chipmunk stores seeds and nuts in their dens before hibernating, while beavers, and most rat or mouse species will provision food in their homes. For birds, the main species that store food are members of the Corvid family like crows, ravens, and jays, two species of woodpeckers, nuthatches, chickadees and titmice. Loggerhead Shrikes, and possibly owls or hawks may temporally store food to feed young or hide it from competing species. Below is a list of birds and animals that routinely store food.

Crows and ravens may carry items for miles. 

Common Crow: Common Crows store a variety of food items throughout the year although they are most likely to hoard nuts from hickories, oaks, beeches, and chestnuts during the autumn. This species of crow lives in family units or colonies in forested areas and usually hides nuts and seeds in tree hollows, under stones, or in the ground. Crows may also hide meat, large insects, or food picked from waste bins to hide it from other birds. It is not clear if Fish Crows stores food as extensively as the Common Crow. The Common Raven also hoards food. 

Blue Jays often hoard feeder items for later use.

Blue Jay: Blue Jays readily stockpile nuts from oaks, hickories, beeches, chestnuts, and pines from late summer through winter. They also take large amounts of food from birdfeeders stocked with peanuts, sunflower seeds, or chopped tree nuts to hide in tree holes, crevices, or in the ground. Jays may also hoard during the summer. 

Loggerhead Shrike: Shrikes create larders by impaling their prey to thorny trees like hawthorn, or honeylocust or to manmade objects like barbwire and chainlink fences. These predatory songbirds often store grasshoppers, cicadas, small rodents, lizards, and other songbirds for later use or to feed young. Pairs fiercely defend sites from marauding crows, jays, or opportunistic mammals like raccoons or foxes. Birds of prey like owls and hawks may also temporally store prey. 

Red Bellied Woodpecker grabbing peanut as a Mockingbird guards the suet.

Red Bellied Woodpecker: The ubiquitous Red Bellied Woodpecker is a scatter hoarder like the Blue Jay with individuals or pairs storing nuts, seeds, large insects, and items from bird tables throughout the year.  Acorns, beechnuts, and hickory nuts are most likely to be stored long-term with the majority of items stored in the autumn and retrieved during the winter. Other items are hidden short-term to outsmart squirrels, crows, jays, or even agile nuthatches that try to plunder caches. Most items are wedged between bark, in crevices, or in human structures like telephone poles, wooden fences, or siding. 

Red Headed Woodpecker: The Red Headed Woodpecker is a colonial woodpecker that creates small larders near roost and nest trees. While this woodpecker does not create massive pantries of acorns like the Acorn Woodpecker out west, they do stockpile as many acorns, and nuts as they can find. This woodpecker will also store large insects, and small vertebrate prey items, as well as fruits for short periods of time. Items are usually wedged into bark, dead trees, or drilled holes in trees or decayed posts. Red Headed Woodpeckers will defend their hoards from other birds and squirrels.

Brown Headed Nuthatches can store large amounts of food in larders. 

Brown Headed Nuthatch: This nuthatch creates small larders that are scattered across several trees with pine seeds and other conifers seeds making up the majority of the stockpile.  Almost all items are wedged behind bark or in tree crevices and  manmade structures. As a colonial or gregarious species, this nuthatch is often seen in groups of 5-20 birds and may defend sites. Nuthatches often hoard sunflower seeds, peanuts, chunks of suet, or other items and will fly back and forth from feeders to save up food. They may do this to avoid competition with other feeder visitors or larger birds like woodpeckers. There is also interspecies competition between Brown Headed Nuthatches and Pine Warblers over pine seeds with the latter not known to hoard food. 

White Breasted Nuthatch: This ubiquitous nuthatch stores small amounts of food throughout  the year although it does not creates larders. Pairs or individuals may store nuts, seeds, or birdfeeder items in nearby trees, sides of houses, or even plant stalks in a garden or weedy field. Other food items are stored short-term to hide it from other songbirds.

Red Breasted Nuthatches are normally seen in Wilmington when conifer seeds are scarce up north.

Red Breasted Nuthatch: Like White Breasted Nuthatch, this small nuthatch usually hides seeds or nuts to avoid competition or as an insurance policy for rainy, snowy, or windy days. This bird also depends on conifer seeds and will venture outside of the boreal regions of Canada or the Appalachian Corridor when spruce, fir, hemlock or White Pine seeds are scarce. 

Chickadees often hide food from other birds and may move items several times. 

Carolina Chickadee: Chickadees will stockpile individual seeds, nuts, or insects over a short period of time during any month of the year. Chickadees may do this to hide food from other chickadees, or more aggressive nuthatches, titmice, and woodpeckers, or to ensure a steady food supply on rainy, windy, or cold days. Chickadees and titmice will often wedge items in crevices, plant stalks, bark, manmade objects, and even hanging planters. Since chickadees often hoard sunflower seeds from bird tables, there may be random sunflowers growing out of flowerpots, or other unexpected locations. 

Titmice are less likely to store up food and mostly do so in autumn.

Tufted Titmouse: Like Carolina Chickadee, except that titmice store food less prolifically and often to hide items from other birds. 

Grey Squirrels burry hundreds of nuts, creating new trees in the process.

Squirrels: Grey and Fox Squirrels will spend the summer and autumn stockpiling nuts, and seeds from various trees to prepare for winter. Since neither squirrel species (nor the Flying Squirrel) hibernates, they must ensure there is a supply of food through the winter. Squirrels burry nuts in soft soil or in out of the way spots like tree stumps, or crevices. Nuts and seeds are stored in scattered locations with hundreds of items hidden at a time. While many caches end up being pilfered by other squirrels, groups of crows, jays, or local Red Bellied Woodpeckers, there are more than enough food stored for a family of squirrels. Many items are forgotten, allowing new oaks, hickories, or other trees to sprout. Squirrels store up large amounts of birdseed as well, meaning that the majority of the items that local colonies raid from bird tables ends up being buried. This may be part of the reason why volunteer sunflowers, millet, corn, and milo plants spring up in gardens well-away from the bird feeders.  

Ecological Roles 

Oaks like these Live Oaks depend on squirrels and birds for seed dispersal.

Food caching can benefit animals by ensuring a steady food source for times of scarcity, or by keeping precious items safe from competitors. However, food stockpiles can also benefit the ecosystem in a number of ways. 

• Forgotten nuts by squirrels, crows, and jays can allow trees like oaks, hickories, beeches, and formerly the critically endangered American Chestnut to spread to new areas. Birds like jays, crows, and nutcrackers can can carry nuts very long distances.

• Cache raiding is a easy way for opportunistic birds or mammals to get food during the winter

• Stored food is very important for animals in the Far North such as Grey Jays, Boreal Chickadees, Common Ravens, and Northern Shrikes. Spoiled food larders due to warming temperatures could jeopardize winter survival or breeding success

• Stored items may also feed or shelter insects