This is the time of the year when you hear a lot of drumming in the trees. It’s mating time for the acorn woodpecker, and he uses this sound to attract a mate.

It is a common sound in springtime, but the drumming is also a display to mark territory. It consists of two to 20 evenly spaced taps, usually on dead branches, which provide good resonance. It can also be performed on telephone poles or even on your house, to the great dismay of the humans inside who are trying to sleep late. At other times of the year, the drumming is used to communicate with the group.

The acorn woodpecker is a medium-sized bird with bright plumage and a black back, white underparts, red head, and white surrounding the eye, so they are easy to recognize. They tend to spend a lot of time tending their granary, so they are also easy to observe because they stay for some time in one spot. Plus, you may see a collection of them, because they live in a group of up to 15 birds.

Photos courtesy of Placerita Canyon Nature Center Associates

The granary is their food reserve; they drill holes with their bill so they can hide enough acorns to last through the winter. They use branches to create the granary, but any wood will do. They even drilled holes in a bulletin board at Walker Ranch and filled it up with acorns for a rainy – or hungry – day. They can hide up to 50,000 acorns in one granary, so the whole group has to be dedicated defending the place.

After the acorns have been stored for a while, they dry out and need to be moved to a smaller hole with a better fit, so the woodpeckers are constantly working and rearranging the granary.

They eat the acorns and also enjoy the worm that develops inside the acorn. They also catch flying insects, ants, beetles and lizards, and they eat fruit, lick sap and even eat eggs of their own species.

Imagine drumming full speed on a tree and digging holes in the bark to hide acorns. How is it they do not get headaches or even brain damage?

The impact of banging your head against a hard surface 20 times per second seems traumatic, but they are well equipped to do this. Their brain is small and is packed tightly inside the skull, so it does not move along with the movements of the head. The brain is oriented differently, so it maximizes the area of contact between the brain and the skull. In essence, the brain is packed in a very tight box so it gets a lot of support and does not get injured.

Carpenters wear safety goggles when they cut boards, and woodpeckers have something similar as a built-in accessory: a nictitating membrane that closes to protect their eye from wood chips, that they can see through to do their work.

Carpenters sometimes wear a face mask to avoid breathing dust. Acorn woodpeckers have another adaptation: their nostrils are slit-like, so not much can come through, plus they have special feathers to cover them even further.

Their beak continues to grow throughout their life, and because it is a tool that gets lots of use, it is very primordial. Earlier, I wrote they like to drink sap and grab little insects; they are well equipped to do so. They have protractile tongues they can project out of their beak that are sticky and covered with spiky hair at the tip. Again, that is another very useful and effective tool.

Their tail has stiff feathers that help them stay in place when they are working in the tree. To help even more, they have zygodactyl feet. That means they have four toes; the first and the fourth ones face backward, while the second and the third face forward. That helps to grab branches securely. All of these adaptations are important for a bird that can manage to walk vertically up (or down) a tree trunk.

Acorn woodpeckers are gregarious birds, but nowhere does it show more than in the way they mate. They live in a group that has one to seven breeding males and one to three breeding females.

It gets complicated, so read slowly – I am getting lost myself – not every bird will mate each year, but the female can mate with up to four males. All members of the group are close relatives except the co-breeding males. It is a sort of commune, and they seem to prevent interbreeding with this cooperative approach.

The eggs are laid in a cavity in the tree – a round hole that you can see on a trunk or large branch. All of the females lay their eggs in one single nest, but each female destroys the eggs that were in the nest before she lays her own eggs. Consequently, one third of the total number of eggs gets destroyed. The eggs get eaten, so there is no food lost (this is especially important for females laying eggs and needing the energy).

Once all of the females have laid their eggs, they leave the eggs alone, and the eggs are incubated by all members of the group. When the eggs hatch, the babies are also fed by all of the members. Young woodpeckers stay with their community to help feed the babies for a few years. The size of the group can be up to 15 birds.

If the community is large and the juveniles do not get a chance to mate, they will check out other colonies up to 10 miles away from home to be accepted and be able to mate in the new colony.

It is a complex and active community life that had been studied in depth because it is so unusual and interesting.

The acorn woodpecker is a beautiful bird, very vocal and with a busy lifestyle. It is one of the easiest birds to observe at Placerita; there is a large granary before the Walker’s cabin and a few sycamores at the beginning of the Canyon Trail where you can be sure to find them.

Come by now in the springtime to see how many woodpeckers you can spot.

Evelyne Vandersande has been a docent at Placerita Canyon Nature Center for 27 years. She lives in Newhall.