Showing posts with label winter migration. Show all posts
Showing posts with label winter migration. Show all posts

Wednesday, December 14, 2016

A California "Snow" Storm: A Winter Miracle in the Great Valley


People don't usually hear a great many good reasons to visit Modesto and environs. Forbes and others often put our Great Valley towns on the "worst places to live", but I think they really miss something when they do this sort of "expose". We grow most of the nation's food supply for one thing, so folks could be a little more appreciative of what we do. But it's really something else that few people are aware of, even those of us who live here. It's the magic of the season, the fact that we are a winter wonderland. The "snow" has nothing to do with precipitation, though, it has to do with millions of refugees from the snowbound northlands. They are Snow Geese. And Ross's Geese. And White-fronted and Aleutian Cackling geese. And thousands of Sandhill Cranes as well. In winter, the Great Valley becomes an American version of Africa's Serengeti Plain.
Snow Goose at the San Joaquin River National Wildlife Refuge

Hundreds of years ago, before the European invasion, the valley was home to tens of millions of migratory birds, but with settlement and development, 95% of their original grassland and river flood plain home disappeared. The birds could have been wiped out entirely, but a few visionary people worked to preserve a bit of the original valley habitat in an effort to save as many birds as possible. The result was a string of federal, state and non-profit run wildlife refuges that form a pathway down the 400 mile length of the valley. The birds will take refuge from October to March, when they begin making their way back north for breeding in the Arctic.
Aleutian Cackllng Goose (Branta hutchinsii) at the San Joaquin River National Wildlife Refuge. Several decades ago, there were only 600 of them left. Today there are around 200,000 because of conservation efforts in both Alaska and at the San Joaquin refuge (their primary winter home)
A great many people right here in the Modesto area are unaware of the Christmastime miracle that takes place each year. It's not hard to see incredible things just a short drive out of town. Only eight miles west of the biggest shopping mall in the region, on Beckwith Road, the San Joaquin River National Wildlife Refuge offers a viewing platform where one can see tens of thousands of migratory geese all at once. The best times are early in the morning and in the afternoon close to sundown. I took the video below at about 4:15 this afternoon during a short break from final exams at the college. Even with the YouTube compression, you can see tens of thousands of geese taking wing. You can hear the cacophony, but there is nothing like seeing and hearing it in person. The ground literally vibrates as the birds take to the air.


The spectacle is amazing, If you live here and you've never seen it, check it out right now! If you are from the Bay Area and are rushing to the Sierras for a ski day, take a short detour. It's worth your time. And if you are a birder, we are a winter paradise. More than 300 bird species have been documented in our area, and many of them can be seen during the winter season when the pickings are poor in other places (a lot of those disappearing birds come here!).

Saturday, November 8, 2014

A Different Canada Goose, the Cackling Kind: Evolution on the Continent

Isolation brings about evolutionary change, and the Canada Goose clan has been doing some changing over the last few thousand years, especially in Hawaii, but also here in California. Today's blog is cross-posted from my new birding blog, Geotripper's California Birds.
If you've ever been accosted by a Canada Goose at the local park, pictures like these might give you the shivers. If one of them can deliver a nasty bite, just imagine what a few thousand of them can do. But take heart, these scenes are no nightmare. They aren't even Canada Geese. The birds occupying this field in the San Joaquin National Wildlife Refuge west of Modesto are Aleutian Cackling Geese (Branta hutchinsii). It's true, though, that before 2005 they were Canada Geese. Allow me to explain.
The Canada Goose lives in many environments, and in some cases particular flocks broke away and colonized different islands or territories (see yesterday's post for an extreme example). The presence or lack of food sources or differences in the nature of predators favored certain traits (size and behavior, for instance) in the young. The geese who summered on the Aleutian Islands were long recognized as a smaller subspecies of the Canada Goose, but recent DNA analysis has led researchers to consider these birds an entirely different species. And so these birds are not Canada Geese, they are the much smaller Aleutian Cackling Geese, which are genetically distinct from the Canada Goose.
The Cackling Geese winter by the tens of thousands in the wildlife refuge a few miles west of my home. It is a stunning sight to see so many of the birds in one place. From the observation deck on Beckwith Road, one can see and hear thousands of birds taking off and landing, and in general making a racket (cackling, as it were). They have been encouraged to stay here instead of nearby agricultural fields through the planting of corn and other food plants. In April they will pick up and leave, headed north to breed in the Arctic.
The refuge is also home to thousands of lesser Sandhill Cranes. We could just make out a flock of them in the far distance. Snow Geese also winter in the area. There were five of them among the thousands of Cackling Geese yesterday, looking mildly confused. They usually arrive in large numbers in late November or early December.
"George, are you SURE this is the right place? Shouldn't you have asked directions in Oregon?"
As we were standing and watching the flocks there was a tremendous BOOM, and thousands of the geese immediately took flight. A huge dust plume over to the west revealed where the explosion had come from. And why.

It was a huge net. Several dozen of the birds had been trapped and for the next few minutes we could see Fish and Wildlife employees tagging them.

As usual, the picture quality from YouTube sucks (the compression process I suppose), but you can get a sense of the cacophony of sound from the flying geese from the short video below.