We’ve had a very slow start of the Fall 2025 owl banding effort.
Two weeks in, a total of 17 Northern Saw-whet Owls have been banded- all hatch-year birds except for 3 second-year adults.
Rain almost every night has limited the effort so far; After days of rain, we finally had good weather last night (Sep 17) and banded 5 birds.
First Northern Saw-whet banded during the Fall 2025 effort
An audio lure for owl banding can be constructed from a few inexpensive / commonly-available parts. For this lure, I am using a small MP3 player module with a built-in amplifier; this module can play files directly off of USB flash drives or micro-SD cards.
All it needs is connection of a power source and a speaker.
There are many variations of this kind of MP3 player module availalble. I chose this one due to the larger built-in amplifier and an actual knob for power/volume (most use buttons); the analog volume control is just a personal preference.
In the past I’ve used heavy SLA (sealed lead acid) batteries in this kind of lure. But recently I’ve switched to using off-the-shelf Lithium Ion power banks combined with USBC PD adapters that provide 12VDC. These power banks can be swapped out quickly and charged with standard USBC chargers.
The speaker is an outdoor waterproof deck horn. The whole assembly is mounted in an old waterproof Pelican case (which is no longer waterproof due to all of the holes I’ve drilled in it over the course of many audio lure variations).
A list of parts with product links is included at the end of this post; all of these parts are only examples.
The MP3 player module includes wire pigtails for connection of power and two speakers (stereo output). I’m only using one speaker here but this system could be expanded to drive two speakers.
Power is provided to the MP3 module by means of a 12VDC USB-C PD adapter cable.
This cable has a USBC connector on one end and a barrel plug on the other end.
To make the connection to the MP3 module’s power wires, a spring-terminal barrel jack is an easy solution. These barrel jacks are also available with screw or solder terminals.
Alternately, the barrel plug on the adapter cable could be cut off and the wires spliced with wire nuts, solder, WAGO connectors, etc.
The audio lure file (mp3) is saved on a MicroSD card and inserted into the ‘TF Card’ slot on the player:
Components used above:
Amazon links provided but all of these parts are available from many sources.
| Component | Sources |
|---|---|
| MP3 player module | https://www.amazon.com/Bluetooth-Amplifier-Decoder-Microphone-Player/dp/B0DRX5VP5B |
| Deck horn speaker | https://www.amazon.com/Indoor-Outdoor-Horn-Speaker-Impedance/dp/B002UL0WH8 |
| USBC-PD 12V power cable | https://www.amazon.com/HSZJsto-5-5mm-Charging-Charger-Output/dp/B0CBNQN7CR |
| Spring terminal barrel jack | https://www.amazon.com/JacobsParts-Barrel-Screw-Connector-Electronics/dp/B01NAYPUAY?th=1 |
| USBC PD power bank | Many possibilities; this is the bank used above: https://www.amazon.com/Anker-PowerCore-Portable-Charger-Compatible/dp/B09VPHVT2Z |
May/June 2025: One of the local owl nest boxes gained a resident.
Seven eggs were laid, but only one hatched.
Owl banding has started a bit late here in Homer, AK this year. The nets are usually set up during the last week in August, but near-continuous bad weather delayed things. Nets were finally set up on Sep 1, and banding efforts started on Sep 2.
As of tonight (Sep 11), 24 Northern Saw-whets have been banded- all hatch-year birds.
After a few nights of banding, this location’s 2000th Northern Saw-whet Owl was banded.
We almost hit #2000 the previous night, but one hold-out preferred to watch the proceedings from the trees instead.
Banding will continue through the end of October; I try to open nets every night that weather permits.
Banding has been slower this week due to all the rain, but there were still owls to be banded. The 200th owl for the season (a hatch-year Northern Saw-whet Owl) was banded on Sep 23.
Banding results for the week:
| Date | Northern Saw-whet Owl | Boreal Owl | Notes |
| 9/25/2020 | 4 | ||
| 9/24/2020 | Rained out | ||
| 9/23/2020 | 11 | 1 | |
| 9/22/2020 | Rained out | ||
| 9/21/2020 | 4 | ||
| 9/20/2020 | 5 | ||
| 9/19/2020 | 15 |
After several years, one of the owl nest boxes near the house finally attracted occupants that weren’t squirrels or wasps.
A pair of Northern Saw-whets raised four chicks; they fledged in early June. All four were banded at the end of May.
The adult seen at the box could be identified due to the aberrant feather growth next to the right eye. This owl was caught during Fall 2019 as a returning visitor; she was first banded here in 2014.
Things started picking up a bit last night.
Six owls were banded: four hatch-year Northern Saw-whets and two hatch-year Boreal Owls.
The Boreals were the first for this season. Only three Boreals were banded during Fall 2016 (down considerably from previous years), so this is a good start.
Boreal Owl banded on Sep 4, 2017
The season’s first Boreal Owl showed up on Sep. 6.
Over the past few nights:
Sep 8: 1 Northern Saw-whet Owl (rain closed things down early)
Sep 6: 3 Northern Saw-whets and one Boreal Owl
Sep 5: 4 Northern Saw-whets
Sep 3: 2 Northern Saw-whets.
All of these birds (Sep 3 – Sep 8) were hatch-year birds except for the Boreal Owl (2nd year).
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.
Audio Lure
Inside of the audio lure, showing SLA battery, amplifier/MP3 player, and charging jack
Amplifier / MP3 player, made by ‘Lepai’
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:
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
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.
Sep 7: The station’s thousandth owl was banded last night. This was the busiest night of the season so far, with 17 hatch-year Northern Saw-whets banded.
Photos of the station’s thousandth owl:
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