Saving Some for Later: Caching in Birds

Wednesday, February 3, 2021

We define caching as the behaviour of storing or hiding something away for future use. We are all familiar with this, particularly over this past year or so (see: toilet paper 2020). However, birds are known, expert cachers. This behaviour in birds is particularly prevalent starting in the fall as we approach harsher winter conditions where food could be scarce. Some birds can store hundreds (yes, hundreds) of seeds or nuts per day. So when you see repeat visitors to your feeders, it is not necessarily because they are eating a lot of seed, they most likely are storing it somewhere. Even more amazingly, they can remember where they have put all of these seeds, for the most part anyway. 


Birds such as chickadees and nuthatches typically cache one by one, under tree bark or in crevices in tree branches.  You may even catch them doing this under your shingles! According to Professor Diane Lee at Cal State University, Long Beach, every fall the part of the chickadee's brain responsible for remembering where things are, expands in volume by approximately 30%, stays big during the winter, and then shrinks back in the spring. They typically cache within a few hundred metres of the source of the seed. 


A White-Breasted Nuthatch caching a seed underneath tree bark. 

A White-Breasted Nuthatch caching seeds underneath shingles. 

Blue Jays also love to cache and have specialized adaptations that help them do it more effectively. Blue Jays carry food in their throat and upper esophagus, an area often called a “gular pouch.” They may store 2-3 acorns in the pouch, another one in their mouth, and one more in the tip of the bill. With this adaptation, they can carry up to 5 acorns at once (or the equivalent size of other foods) and store it somewhere for later. Some studies have shown that in a single fall, one Blue Jay could cache 3,000-5,000 acorns. They can sometimes travel up to 3km to cache their treasures. 

A Blue Jay loading up with multiple peanuts 

Even birds of prey will cache. When owls have more than one meals worth of food, they will store meals for later. In the trees surrounding their territory, you may spot mice they have caught on branches in trees. 

This behaviour is widespread in the animal community and you will also notice other species in your yard caching, including Red Squirrels, Eastern Grey Squirrels and Eastern Chipmunks. Just for cuteness value, I will add in a photo of a chipmunk with its cheeks more than full! 


An Eastern Chipmunk with its cheeks bursting at the seams! 

Take a closer look at the birds and other animals in your yard. Watch as they collect seeds. Are they only taking one and flying to somewhere close by to store it? Are they loading up with multiple and flying further away? Are they weighing the seeds to try to make the best selection? 

As always, happy watching! 


Warmly, 


Heather


2 comments:

  1. Great article. I learned a lot. Now I know why Chicadees and Nuthatches are so busy on our big tree.

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    1. LOL Busy little things aren't they! Thanks for reading!

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