Owl Banding: Fluctuating Captures


Nick and I are just getting off of a three day stretch of complete banding nights. As I had mentioned before, our protocol entails running nets from dusk to dawn with hourly net checks. We have come to figure out that this is not an easy task but it is getting easier as the banding days are becoming more consistent. The last three days have exhibited fluctuating owl captures with a total of 25 owls. This has brought high hopes that more will be moving through the area. If the captures continue to increase or even stay at this rate, it will be a great season of spring owl banding.

On the night of March 27th, going into the morning of March 28th, we captured 7 Northern Saw-whet Owls. We are seeing a diversity of age classes among the NSWO captures. Ageing NSWOs is a very unique and exhilarating process. Most birds have a pigment obtained in their feathers called porphyrin. When the porphyrin is exposed to UV light or UV radiation the pigment undergoes a reaction, causing the newest feathers to fluoresce bright pink, leaving the old feathers dull brown. This process permits ornithologists to accurately classify and age adult owls.  Every owl showcases slightly different molt patterns, based on their age but predictable molt patterns can be observed. However anomalies and outliers will always occur.

At this time of year, this is a typical molt pattern of a second year bird. The uniformity of the primaries and secondaries tells us that this bird hatched in the summer of 2016.
This molt pattern classifies this bird as a third year, which often exhibits the replacement of the outermost primaries and innermost secondaries. This bird hatched summer of 2015.
This pattern would be classified as an after third year bird. which hatched in the summer of 2014.

Our second consecutive day of banding brought in a whopping 10 Northern Saw Whet Owls, which took place during the night of March 28 going into the 29th. This banding night we had two recaptured birds which had bands on them from previous banding operations. Both birds were aged and sexed as after third year females and we are currently waiting to hear where they were originally banded. With high expectations going into the third night we managed to net 8 more little Saw-whets on the night of the 29th going into the 30th.

To our surprise, we were greeted by an American Woodcock in net 6 on our closing round. These birds are in the family Scolopacidae, with their close relatives, sandpipers and phalaropes. Unlike their cousins that prefer shorelines and aquatic habitats, these birds prefer moist overgrown fields and open woodlands. During the spring season  we have the opportunity to witness the breeding display of woodcocks. This includes a high acrobatic flight preformed by the male while singing an ascending  flute like song to serenade the surrounding females.

Unfortunately, tonight the weather has been uncooperative. The nets remained closed due to snow flurries and high winds. Stay tuned until next time my owl loving friends. Next time on MSRW owl banding blog we will report where our two mystery recapture birds came from.






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