Today, while eating my lunch, I was given over to pondering a question. I’ve always known that the early bird gets the worm (I mean, it’s a fact of life right?), but how is it that the late bird also gets the worm?   You see, birds – especially those of the robin ilk – need to eat morning, noon, and evening and can’t afford to stop at the early worm.  They engage in worm hunting throughout the mid day, when the worms themselves aren’t active, and yet they still are successful.

  It is not my current intention to go in-depth into the subject of how robins find worms.  I do not know the whole answer, nor does anyone else apparently. Type the phrase “how robins find worms” into your search engine and you’ll come up with some conflicting answers. That they see ‘em is the primary answer, but the jury is out as to whether they hear ‘em as well. You’ve seen the birds perform the ritual a million times: a quick head down run ending in an erect pose, a pause followed by a tilt of the head, a jab or two, and up comes a worm held firmly in the beak.

  As a creature with oppositely facing eyes, the robin has to tilt its head sideways in order to get a vision fix on a close object such as a worm. It has little binocular vision capability and must rely on the high resolution sharpness provided by a single eye for detail work. This head tilt has also been construed to mean that the bird is directing an ear opening toward the ground and using sensitive hearing abilities to pinpoint prey location. There has been at least one experiment that seems to bear this out this latter theory. In that situation a robin was able to locate some mealworms without any visual clues. 

  Earthworms are covered with fine bristles and they do make somewhat of a quiet racket when pushing up against dry leaves.  It is entirely possible that the keen-eared robin is capable of hearing these sounds, but the head tilt is definitely a vision related posture.  The overall answer is probably a combination of visual clues and auditory clues. Either way, the worm is history.

  My lunchtime question was prompted by an opportunity to watch a robin work the bark chip mulch around some shadbush plantings. I was taking a break from presenting a whole slew of nature programs as part of the annual River Rouge Water Festival on the campus of the University of Michigan at Dearborn. My lunch break was 25 minutes long, so I had the time to sit outside on a picnic table while consuming my complimentary turkey wrap (I only do this program because of the free food). 

   Apart from watching the masses of 4^th and 5^th graders and their befuddled teacher escorts walk across campus, my attention was drawn to a single male robin about ten feet in front of me. I fixed my gaze upon the fowl as a way to occupy my time. At first I perceived this activity akin to being forced to read a copy of Redbook magazine in the doctor’s waiting room because all the Outdoor Life mags are gone, but this view soon changed.

  This bird seemed to be having extraordinary luck.  He kept returning to a patch near the base of one of the plantings. With each bite of my wrap, this efficient hunter was downing a worm – about one every ten seconds for a short period. Usually it took a few side swipes of the beak to clear away a piece of bark before the prize was secured. I watched the ground in front of him very closely to see if I could detect any worm motion but was unsuccessful. The robin flew off each time a passing clan of noisy children walked by, but it invariably returned to the same spot.

  It was a cool dry day and I couldn’t imagine why a bunch of worms would expose themselves in the noon hour sun – especially in the presence of killer. There were none in the bark closest to me.  I discovered the secret about the time I was tearing into my huge Macadamia nut cookie and confirmed it by the time I ripped into a bag of Doritos (I told you the free food was crucial here). The robin had an underground partner.

  Every now and then, a section of bark would push up from the ground at the exact point where the bird was operating. A mole was working the soil beneath the bark layer and causing the worms to issue up out of the ground as if they were being electrocuted.  The mole never broke the surface. I can’t confirm that the robin knew what was going on, but then again, I don’t think he cared. There were lots of worms and that’s all that mattered.

  I’ve seen this mole-induced worm terror before. Since earthworms are very sensitive to ground vibrations, the digging action of a mole – a worm predator- will alert a vibratory sense within all worms in the immediate vicinity to seek the safety of the surface. The escaping worms look like they are jumping out of a fire. Once I followed the course of a tunneling mole for several feet by watching the fleeing horde of worms that surfaced just ahead of it.

  Worm hunters – human worm hunters that is – have long employed this trick to get worms up and out. By sticking a rod into the ground and tapping it lightly, they imitate the mole’s digging sounds and fill up their bait containers in no time.

  Today was the first time that I saw a non-human bait collector take advantage of this effect. I enjoyed this bit of unexpected dinner theatre. It goes to prove that even mundane observations can reap some reward. One has to feel a little bit sorry for the worms in this case. Normally the surface provides them temporary safety until the danger passes. But when sandwiched between two predators, well, it’s like jumping from the frying pan in to the fire.  Fried worms anyone?