Our Saw-whet Owl fall migration station got underway last week! We are back along the shores of Flathead Lake for our 3rd full season in this location.
After 5 nights of banding we have caught 21 owls! Some of these owls may be locals in this area and others may be migrating through. The data collected at this station is shared locally, regionally and nationally to better understand the movements of the Northern Saw-whet Owl.
All banding, marking and sampling is being conducted under a federally authorized Bird Banding Permit issued by the US Geological Survey’s BBL.
I thought this was just pretty scenery at first, but then I detected the poles of some of the mist nets.
One of the many reasons permits are required to band birds is that purchase or possession of mist nets is illegal otherwise.
Mist nets are just about invisible to birds, and they can get hurt or killed if used improperly. They are also used for poaching and trafficking animals, hence the right restrictions.
Here’s a mist net being set up.
You can see the fine netting which is near invisible at night. Properly set up nets will stop the bird and plop it down into the pouch along the bottom. Nets are checked very frequently to remove birds ASAP to minimize stress and chance of injury. They’ve got a lot of flying to do, and they need all their health and energy.
Birds average about a 20% loss of body mass in the few days it takes to migrate.
Wing and mass measurements can be used to gender an owl to a surprisingly high degree of accuracy.
They have better tables in their field manuals than I can find online, but this plot can demonstrate the cutoff is fairly easy to see. Most raptors have a good amount of sexual dimorphism where the females are larger and heavier.
A neatly organized station. I see banding pliers, it looks like a small carrier for transporting owls from the nets, a map of net locations on the van door, and apile of documentation for recording readings and probably a sexing chart and tape measure or ruler and a scale somewhere in there.
Not sure what the floppy disc storage bin is for. 🤔
Return to Zork, obvs.
I suppose there is a lot of downtime… 😄
How do they safely catch them?Internet is slow. Answered already. Mist nets
I just saw your update as I was about to post an answer, so you get it anyway.
Here’s some pics where it’s easier to see what’s going on with the mist net.
Different sizes of mesh are for catching different things. Too big and too many birds get through, too small and you’re catching too many things you don’t want and what you do want to catch will bounce off, so nets are sized and set up to catch a specific animal. Only catching what you’re after is going to minimize the chances to hurt anything right from the start. Proper vertical slack is given to make pockets in the netting of proper depth.
Birdy will hit the net and tumble down into the pocket and get feet, beak, wings caught up in the net and try to minimize movement. Care is taken to make sure they dont get caught near the ground/obstructions they could hit themselves on trying to get out. Nets should also be checked at least every 15 minutes, so nothing is stuck there longer than necessary.
Birds are removed by untangling them. If any are trapped together or in a situation injury may be more likely, they’ll be removed first.
I found a manual on using the nets with a lot more details for anyone interested in more specifics on how the nets work or more steps and advice for removing birds. Section 4 / Page 6 is where the good stuff starts, but I’d recommend at least skimming the whole 10 pages after, there is a lot of cool info.
OotY on deck! Atteeennnn SHN!
