Have you ever seen a bird hiding food? Perhaps it’s a woodpecker wedging a nut into a tight hole, or a jay burying a nut in the lawn, or a nuthatch tucking a seed under a piece of bark. Just like we will fill our pantries, cupboards, and fridges with food, many birds will also store food – a process called caching.
What Is Caching?
Caching is more than just tucking away a snack for later. Different birds will very conscientiously gather and store copious amounts of food – seeds, nuts, even dead insects or other prey – with the intent of revisiting those stored supplies, called caches, when hunger strikes in the future. A cache might be a single nut pushed into the dirt and covered carefully with bits of grass, leaves, or debris, or it might be a meticulously gathered stash of seeds tucked into a wedge between two close tree branches. A cache might even be a dead mouse or other small rodent stabbed onto a barbed wire fence or sturdy cactus thorn.
Birds typically start caching food in mid- to late summer, and continue their frantic storage efforts for as long as food supplies hold out through the autumn and even into early winter. They will store morsels, treats, and meals in many different locations, even returning to those locations to inspect their stores or add more to the menu. In fact, ornithologists have been astonished at how accurate birds’ memories can be for where they’ve stored food. An individual bird might store food in hundreds or even thousands of different locations, with a keen memory to return to those locations days, weeks, or even months later to retrieve the food. Chickadees and titmice even grow larger brains during their caching periods to enhance their memories and remember storage locations, while it is believed that other birds may simply “stock” food in their most comfortable territory so they can re-forage more easily at a later time.
Birds That Cache Food
Many different bird species practice caching, though the amount of food they store, how they store it, and how often they revisit caches will vary. Typical birds that are expert cachers include:
- Chickadees, titmice, and tits
- Jays, crows, nutcrackers, and other corvids
- Screech-owls and small hawks
All of these birds store foods in different ways, but each one has demonstrated the forethought of storing food for times when supplies dwindle.
The Food They Store
Different birds have different diets, so it is no surprise that they will store different foods. The birds’ bill sizes, dietary preferences, and locally available food supplies all impact what treats make up a cache, but the most popular foods to be stored include:
- Tree nuts of all kinds, including acorns, beechnuts, hickory nuts, hazelnuts, and pine nuts
- Both shelled and in-shell peanuts, as well as peanut chips
- Seeds, particularly shelled and in-shell sunflower seeds, sunflower chips, and pinyon seeds
- Freshly killed prey, including small birds, mice, voles, and large insects
- Mealworms offered at feeders
One bird may store almost exclusively the same type of food, or it may have different caches of different food types throughout the season depending on which foods are ripe, most readily available, and easiest to store.
How They Store It
Just as every birder has a different pantry, personalized fridge organization, or a different way to store birdseed, different birds also store their food differently. Some birds tuck their treats underneath fallen leaves or garden mulch, while others wedge small bites into the rough bark of a tree or between two tight branches. A wood pile or rock pile can be an excellent place to store food, and birds might even make use of the cracks and crevices of soffit, awnings, shingles, gutters, and eaves to hide a bit of food. Some birds drill their own storage units, like the granary trees of acorn woodpeckers, while others opt for hollow tree cavities, deep knotholes, or other natural hiding places. Sharp branches, barbed wire, and cactus spines can also be storage spots for carnivorous birds that cache uneaten prey.
After food is hidden, birds may revisit the cache not just to feed or add extra supplies, but also to adjust their storage. Rearranging a bit of nearby debris, moving a nut to a different hole, or more tightly wedging seeds in crevices can help keep the cache safe and memorable so it can be refound when needed.
The Role of Caches
Caches are more than just food storage for feathered survivalists. In many parts of forests, woodlands, and other habitats, caches will also support other hungry guests who will raid any caches they are lucky enough to find. Seeds and nuts that are uneaten in the spring when new foods become more desirable may sprout into new trees and plants, rejuvenating the habitat so fresh plants can then create fresh seeds and nuts in the future. Birds that move foods greater distances from the source also help spread and grow habitat, expanding their own suitable habitats and territories over time.
Caching is a remarkable adaptation birds use to keep themselves fed, and it is a remarkable behavior for birders to witness. I’ve seen black-capped chickadees darting away from feeders with plentiful seeds, and scrub-jays tucking peanut after peanut after peanut away under leaves on the lawn. I can’t quite explain the scrub-jay that buried a cheese puff in the yard, even covering it carefully with a dry leaf and a bit of grass, but hopefully he, too, enjoyed revisiting his snack storage.
What birds have you seen caching? Share your experiences in the comments!