Audio Lures for Owls

Over the years I’ve built and used a number of audio lure systems for Saw-whet banding.

At Holiday Beach, around 2001-2002, we used a cassette deck and a P.A. amplifier; we had power in the banding station, so we ran a long cable out to a speaker at the nets.  We used endless-loop answering machine tapes in the cassette deck.  We later replaced the tape machine with a CD player set to repeat a track.

My current setup in Homer, AK has to be battery-powered.  The system has gone through a bunch of changes as I tried out various amplifiers and playback mechanisms; initially this consisted of a Pelican box with a 5AH sealed lead-acid battery, a small MP3 player, and an amplifier scavenged from a pair of computer speakers.

The system now still uses an SLA battery (7.5AH), but I’ve switched the amplifier and MP3 playback to a small self-contained unit found on eBay; this unit plays MP3 files off of an SD card (or USB flash drive) and includes a stereo amplifier.  It drives a pair of marine deck horn speakers.  A single switch turns the unit on or off; the SD card contains a single 1-hour-long MP3 file that alternates between NSWO and BOOW every 15 minutes.  This file auto-plays and repeats as long as power is on.

This system goes quite a while on a charge.  I typically charge it about once a week; use is several hours per night.

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Audio Lure

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Inside of the audio lure, showing SLA battery, amplifier/MP3 player, and charging jack

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Amplifier / MP3 player, made by ‘Lepai’

 

Smaller, lighter lure

I’ve also built a couple of smaller, lighter audio lure boxes for others; Holiday Beach now has one of these. This version is made mostly from cheap eBay parts:

  • mp3 player board with remote
  • stereo amplifier board
  • 4x 16650 Lithium batteries
  • Plastic enclosure
  • Deck horn speaker

This variant also plays a single MP3 file off of a micro-SD card and auto starts/repeats on power-up; a single switch on the outside of the box controls power.  It also has a fairly useless remote that came with the MP3 player board; this could be useful for changing the volume or selecting among multiple tracks (if present), but for NSWO banding it’s probably not of much use.

 

Smaller MP3 lure with remote

Inside- batteries, amplifier, and MP3 player board

Lure with warning – the sticker seemed appropriate for this application

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Mono amplifier board (L) and MP3 playback board (R)

This system weighs a LOT less than the larger SLA battery-powered system.  An external 16550 charger is used to charge the batteries.

The next iteration of this thing will probably use an even simpler MP3 module I just bought; it includes an amplifier on-board.  It remains to be seen whether or not this new board’s amplifier is sufficiently powerful.

Oct 21

Another good night.

Eight new owls were banded; all were hatch-year Saw-whets.

Additionally, one Saw-whet that was banded 6 days ago made a return visit.

Like the previous night, the owls started showing up around 11pm.  Nets were open for 6.5 hours.

Oct 20: Picking up again

Banding is picking up again; first night for a few days without rain/wind.

Eleven owls banded tonight: ten Northern Saw-whets and one Boreal Owl.  All but one of the Saw-whets were hatch-year birds; the only adult was a 2nd year bird.

Nets were open for 6.5 hours- the owls didn’t start showing up until about 11pm.

October 17-18

Banding has been slower for the last couple of nights.

Oct 17:  Three hatch-year Northern Saw-whets were banded.  Additionally, a Saw-whet banded earlier this season was recaptured.

Oct 18: Four hatch-year Northern Saw-whets were banded.  Thanks to Malcolm and Maggie Mae for visiting!

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Maggie Mae releases a Saw-whet.  That’s not actually the owl’s shadow…

Oct 16

After a few nights of rain, we had a good night for banding.

A total of 12 Northern Saw-whets were caught; of these, three had already been banded here earlier in the season.  One of these has been in the area for about six weeks.  Additionally, nine new Saw-whets were banded- all were hatch-year birds.

Thanks to Leo, Bev, and Maggie Mae for visiting!

 

Slow for the last couple of days

The last couple of days have been slow, with intermittent rain.

Oct 13: One hatch-year Saw-whet banded before the nets were closed due to rain.  Nets were open for one hour.

Oct 14: Two hatch-year Saw-whets banded; light rain intermittent through night.

Rain is forecast through the weekend.

Oct 12

Saw-whets are still coming through; seven hatch-year birds have been banded tonight so far, including this Saw-whet with an apparently injured eye: the left eye is dilated, but the right seems to be reacting to light properly.  This bird was heavy and had lots of fat, so it’s apparently eating well despite the eye problem.

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