Back in mid-December, a platoon of waterfowl biologists, field technicians and volunteers gathered outside of the entrance to Cameron Prairie National Wildlife Refuge’s Pintail Drive waiting for lesser snow geese to show up. The group could see small flocks of snows dropping into a flooded impoundment up the road, perhaps a quarter mile away, where they would eventually swim to a grist pile provided courtesy of refuge managers.
The purpose
The intent of this early morning foray into the refuge was twofold. One was to capture mid-continent lesser snow geese and attach 25 state-of-the-art (GPS/GSM) tracking devices to them, to identify habitats, movements and seasons important to their overall survival and management.
The second purpose was to study and monitor avian influenza. In late December, the Louisiana Department of Wildlife and Fisheries issued a press release stating that this fall’s migrations have led to a resurgence of the virus in waterfowl and other wild birds. It went on to say that while many recover, some may show neurological symptoms that can lead to death. Moreover, scavenging birds such as raptors and vultures are highly susceptible to the disease.
The goal was to capture as many lesser snow geese on the grist pile as possible using a rocket net. Unbeknownst to the geese, while they stuffed their gizzards with sand to digest their food, LDWF Rockefeller Wildlife Refuge Research Program Manager Paul Link would fire the net in ambush-like fashion making the capture.
Hearing the rocket charges detonate in one long burst, the entire group mobilized, diving into ATV side-by-sides and pickups towing trailer loads of orange crates and floating sleds to the grist pile. Under the net was well over 100 lesser snows that needed to be removed as quickly as possible, where they wouldn’t be further stressed from exposure to the elements.
Once crated, the whole operation went from controlled chaos to a rhythmic banding process. Some of the birds would be collared with tracking devices based upon their sex and health, while others would go through swabbing and bloodletting to test for avian influenza.
a GPS/GSM telemarked lesser
snow goose. (Photo courtesy John Flores)
A sharp decline
The light goose story, which not only includes mid-continent lesser snow geese, but also greater snow geese and Ross’s geese, spans three decades, where their numbers reached unprecedented highs throughout the early to mid-90s, with estimates peaking at around 20 million in 2013 according to Link.
Today, those light geese numbers have precipitously declined. Link said you have to go back to 1987-1989 when mid-continent light geese populations were this low, stating the current Lincoln-Petersen estimates show them to be around 4 million. The Lincoln-Peterson method of estimating uses important band recovery instead of traditional survey methods.
The Light Goose Conservation Order (LGCO) was established in 1999 to reduce adult snow goose survival. The order allowed for a no holds barred approach to regulations, where everything from no plugs in shotguns, to electronic callers with amplified sound, and extended seasons were allowed and established.
Unfortunately, the LGCO was ineffective in lowering adult survival. Chronologically, there was an extreme rise in light goose populations, where there was concern for arctic and sub-arctic habitat destruction (breeding grounds), to a peak population that has now spiraled downward, reaching historic lows not seen since the late ‘80s.
The question is, if the LGCO was unsuccessful in reducing light geese populations, what has caused this serious downturn in just over a decade? With the dramatic decline in light goose numbers, the focus has shifted to productivity.
Link pointed out how GPS/GSM study results can help biologists form a full annual cycle model for snow geese and quantify the relative importance of phases of the annual cycle to explain variations in productivity.
“We’re proposing to capture and collar 20 to 40 adult female snow geese during the next five plus winters,” Link said. “We’ll attempt to mark half in the coastal marsh of Rockefeller Wildlife Refuge and half in the rice prairie region of southwestern Louisiana. Multiple years of marked birds are needed to hopefully untangle the complicated carry-over effects, which is essentially what happens in one season and how it carries over impacting subsequent seasons.”
Avian influenza
Avian influenza is also a concern. Research Professional Deb Carter works for the Department of Pathology in the College of Veterinary Medicine at the University of Georgia/Southeast Cooperative Wildlife Disease Study Group. Carter has been involved in avian influenza research for well over a decade as she crisscrosses the United States annually.
“This study has been going on for 4 years, where we have been monitoring avian influenza in these snow geese,” Carter said. “Early in the study there was no highly pathogenic avian influenza, and then when high path did come in, it became apparent that these snow geese were getting sick and dying and that the high path virus was still in them.
“H5N1 is extremely hard on juvenile snow geese,” Carter said. “One of the things the UGA/SCWDS group is trying to assess is what does the impact of highly pathogenic avian influenza have on snow goose populations.”
No doubt findings over the next several years, particularly if numbers continue to decline, will impact how wildlife professionals across all flyways approach managing light geese populations.
