Who's eating my pecans?

   While harvesting this year's pecan crop, I spotted a few nuts that had their shells broken open by one of the many critters that feed on pecans (photo at right). By just looking at the damaged nuts, I can tell which pest caused the damage.
    A woodpecker caused the deep narrow hole in the nut labeled "A".  With their sharp, narrow bill, woodpeckers punch a hole through the shell  and feed on the kernel inside.  Woodpeckers carry off small native pecans and cache them in tree voids for later consumption. Since they can't carry off large, thin-shelled nuts they simply take a quick bite before getting back to work stealing native pecans.
   Mice will climb up into trees and start gnawing into pecans as soon as the shucks split open. You can always spot a mouse damaged nut by the neat round hole they chew into the side of the shell (pecan "B").  They usually make the hole just large enough to poke their head into the shell and clean out every morsel of pecan kernel.
    A nut with a large, irregularly-cracked hole was attacked by a bluejay or crow (pecan "C"). These birds have large beaks that they use to pound open the shell. Often the nuts are broken in several pieces but they always eat the entire nut kernel inside.
    Wildlife can eat a significant proportion of a pecan crop so its always important to harvest as quickly as possible. The list of critters that eat pecans include not only the three pests described above but also includes squirrels, raccoons, deer, coyotes and turkeys.   

Sapsuckers have arrived

  Every spring, yellow-bellied sapsuckers stop to visit our pecan trees on their flight northwards. Long before the buds of pecan trees start to break, these members of the woodpecker family will drill a series of holes in the trunks of pecan trees (photo at right).  The holes are dug deep enough to allow rising sap within the tree' trunk to leak out. The sap provides nourishment for the birds as well as attracting insects to the sugar rich sap. When the sapsucker returns to it's freshly dug holes, the bird will dine on both sap and insects.
   Looking at the photo at right, you can see a row of freshly drilled holes in the bark. But six inches above that row is a row of old sapsucker holes that have been closed over by growing bark tissue.
   Sapsuckers holes may look bad but they do not damage nut production.

What's up in pecan tree canopies

    While I'm hand harvesting nut samples using a hydraulic lift, I often spot interesting and unusual things up in the tree's canopy that I wouldn't notice with my feet firmly on the ground.

    We have all noticed nut shells on the ground a harvest time that have been chewed by mice. You can see the gnaw marks on the shell and a hole chewed large enough to allow easy access to the kernel inside. But I never realized that mice would actually climb up the tree and start feeding on nuts long before they drop to the ground. The photo above shows two pecans neatly cleaned out by a hungry mouse. Since this was the only nut cluster I found like this, its likely that red-tailed hawks find tree-climbing mice an easy catch.

    In the canopies of unsprayed trees, I find lots of nuts infested with hickory shuckworm larvae. The small white caterpillar with a red head tunnels through the shuck of the pecan and can cause the shuck to stick to the shell (photo at left). 
   

      Hickory shuckworm larvae eventually pupate inside one of their tunnels before turning into an adult moths. But have you ever though about how the moth gets out of the shuck. The photo at right shows a shuckworm pupal case partially shoved out a hole created at the end of a tunnel. Still trapped in its pupal case, this shuckworm moth managed to wiggle out of the shuck until it could break free outside. I've seen several of these pupal cases and every time the case emerges from the shuck tail-end first. I guess makes sense. The moth could use the force of spreading wings to crack open the case then simply back out.  

 

    In one tree, I found nuts with unusually shaped shucks (photo above). The nuts appeared flattened with a distinctive crease down the middle. Although these nuts had not yet split shuck, the shuck had separated from the shell and I could easily peel out the nut. What I found inside was a small nut with a kernel that had grown too big for its shell. 

    This condition occurs when nut size and final shell dimensions are determined during a dry period in late July. A lack of soil moisture during the nut sizing period causes the creation of smaller-than-normal nuts.  Later, ample rain fell during the kernel filling process in late August which, in turn, promoted rapid kernel expansion to such an extent it popped open the shell.  What is interesting to see is how the shuck reacted to the over-expanded kernel. The crease in the shuck is located directly above the crack in the shell. Fortunately, not all the nuts on this tree appeared like this. Most nuts had normal shucks and already shuck split.

    Every fall, I enjoy taking photos of ripe pecans on the verge of falling out of their shucks. This year, I found a nut that was not only ready to fall but one that tickled my fancy (photo at right). Almost like a Rorschach diagram this pecan reminded me of something totally unrelated to pecans. Can you see the helmet, eye slits, and open mouth with pecan falling out?  Or maybe I have an overactive imagination!

hoo... hoo..... is sitting on my bird perch

     Every year when I give grafting schools, I stress the need to attach a "bird perch" on the tree to protect the scion from birds landing-on and breaking-over the newly attached graft. Common song birds that like to perch on new grafts include; red-winged black birds, meadowlarks, and sparrows, bluebirds and starlings.  I never expected that an owl would perch on one of my trees.
    About a month ago, my neighbor stopped to tell me he had seen an owl perched on the bamboo stake I had attached to a tree I had top-worked. He was amazed that my bird perch was strong enough to hold such a large bird.  I knew a pair of Barred owls were nesting on my farm because I had recognized their distinctive call (sounds like--"Who cooks for you, who cooks for you all") earlier this spring. Even though I heard them calling, I never got a good look at them until this week.
    The other evening, I was finally able to photograph one of our resident Barred Owls. The owl was perched on a steel fence post that holds one of my tree cages in place around a seedling pecan tree (photo above). From the owl's perspective, this was the perfect spot to hunt for mice and voles that live in the turf between my young trees. Barred owls can grow to 25 inches tall with a wing span of 3.5 feet. Barred owls will also dine on squirrels, so I hope this pair of owls stays around for many years to come.