Fisher Predating OwlCam Nest Box (5-17-03)

This picture shows the fisher (Martes Pennanti) as it returned for "one more look" after taking the last of the three barred owlets. The attack took place just before complete darkness and was visible only after a Photoshop level adjustment. The nest box tree is protected against raccoons by a 20-inch band of aluminum flashing, but this was no match for the fisher. The sounds even suggested that the fisher may have approached through the treetops and climbed down to the nest. The predation actually took place over two nights with the first owlet disappearing without any clue sometime during the night of the 16th or early morning of the 17th. The reason for the mysterious disappearance did not become apparent until the fisher returned for the remaining two owlets on the evening of the 17th and I reviewed the tape from which this frame was taken. The only noise made by the fisher during the attack was a low volume snorting sound. The owlets were two weeks old at the time of the attack. Both adults were away from the nest at the time of the attack. Had June been in the nest, recordings made over the years of the footsteps of unidentified "night stalkers" approaching the nest suggests that she may have foiled the attack. She responded to such approaches with a diversionary tactic in which she abruptly leaves the nest and snaps her beak at the intruder from a nearby perch. In all of these cases, the unidentified intruders could later be heard walking away from the nest. 

If the notion that animals are not capable of experiencing grief is correct, then June deserves an Academy Award for these sounds, which were recorded when she entered the nest shortly after returning to discover that the owlets were gone. The galloping sound between squeals and at the end is the sound that she normally makes to urge the owlets to eat.

October 10, 2003 Update

A review of a six-hour tape that was recorded between 8pm and 2am on the evening that  the first owlet disappeared provided some surprising insight into the nature of that attack. While only the first thirty minutes were recorded before complete darkness, the remaining sound-only portion of the tape also provided useful information. The video came from the inside-overhead camera, so that only audio recordings of activities outside the nest were available. The first indication of the fisher's approach came about thirty minutes before darkness when a loud thump could be heard on the roof. The owlets were alone at this time, but June quickly did a crash landing in the doorway and entered the nest, only to turn around and climb into the doorway to defend the nest. Over the next hour, the fisher could be heard approaching the doorway many times, but on each occasion, the sound of a lot of scuffling on the rail and in the doorway indicated that she was able to drive it away. These approaches grew less frequent over the next few hours and on two occasions, June went back into the nest and could be heard ripping up prey and feeding the owlets. She returned to the doorway every time the sound of the fisher was heard on the roof or rails. The tape ended at 2am with June still defending the nest. There were no further recordings of activities until 6am when daylight revealed only two owlets in the nest. Three things surprised me about this attack: First, June does not normally defend the nest from the inside when she is hopelessly overmatched. She would normally avoid being trapped in the nest by flying to a nearby branch and swooping down to harass the intruder. Second, she did not snap her beak during the defense. This is her instinctive reaction to a threat, and would probably have alerted me to what was going on. Third, there was no sign of Ward during the six hour ordeal. He normally returns and does a lot of hooting and swooping when the nest is threatened. A review of recordings of the owl that I had assumed to be Ward in the days after the attack showed that it was a younger male barred owl, and not Ward. Ward's subsequent absence throughout the summer and June's marathon hooting sessions make it possible that he perished defending the nest. If he did survive and returns, I will be able to recognize him by his voice, but there is no way to predict what might happen..

Back To: May 17, 2003 Page

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