Exploring Colonia's wild side: a taste of La Arenisca Natural Refuge

A wide walkable forest path in La Arenisca Natural Refuge.

If you are a nature nut, like I am, one of the most interesting spots near Colonia del Sacramento lies just North of the city. It might seem strange to find untoutched native forests and swaths of sand dunes nestled between one of the most agriculture-intense areas of Uruguay and coastal development, but there it is. Thanks to Eduardo, a local landowner and nature enthusiast himself, the small refuge has kept most of its natural traits, and looks promising as a birding destination.

The refuge holds some intriguing habitats, like this coral-tree forest, called a ceibal, with an underlying grassy brush. Here's a potential niche for some rarely seen rail species.

Now, I say promising because it's been mostly unexplored by bird connoisseurs. Even though Eduardo organizes frequent horse riding tours through the woods up to the beach, birding is not his strong point, so who knows what feathered critters could be lurking about. Somebody had to go and see. My curiosity itch started itching, so off I went. My good friend Dahiana tagged along and last Friday we set forth to explore the area.

We were not alone... Eduardo's horses kept us company through the wide forest trails.

I also had another objective in mind: as the refuge is one of the tours I offer, it was important to test walking distances, terrain conditions and the timing of the tour. Our results? 4.82 km walked in 3 hours and 43 minutes; trails are wide and easily walkable, although some muddy crossings could get nasty after rains. Overall a succesfull reconnaissance expedition.

Out on the beach at the end of the trail feeling all triumphant. I´ll be honest... we´re just posing, there was nothing to see but water.... and this is like take 4 of the picture.

Birdwise, we got to see and hear 54 species, not bad for a windy spring day. Most summer migrants haven’t arrived yet, so future visits will likely get higher counts as the weeks pass. Most interesting for me was finding the Tufted Tit-Spinetail so close to the city, it's a small member of the ovenbird family which is not very abundant. We also managed to take some decent pictures, Dahiana proved to be quite good trying out the camera! Just scroll down for a showcase.

One of our first encounters was this Masked Gnatcather, its facial mask reveals it’s a male. Normally hard to photograph, this one was kind enough as to stop his jumping around and pose on an exposed twig. I had time for a couple of pictures and off he went again.

Two trees to the right and we saw this very green Monk Parakeet. One of the most abundant birds for us, it’s considered a pest for agriculture. This one was gathering thorny branches looking to remodel its nest.

I’ve always considered that if you learn only 1 new thing per field trip you can mark it a success. This time it was a little plant, (did I mention I’ve still got loads to learn about plants?). I’d seen it several times before but I never got to know its name, with a picture and a guide book I learned this is the flower of Lantana montevidenesis. A relative of the more commonly known and invasive Lantana camara, which also grows natively in the same place.

Another new find were male and female Turquoise Emperors (Doxocopa laurentia). I'll leave it to you to figure out which is which.

Great Kiskadee nests are easy to idenfiy: a basketball-sized ball of yellow grass with an entrance. This bird is EVERYWHERE, it lives in every habitat type, from marshes to city centers. As you can guess, it’s very adaptable, and it uses several strategies to get its food. I’ve seen it hover above water like a kingfisher, steal worms from thrushes, smack a mouse dead and swallow it whole, and steal dog food from the bowl. After nuclear holocaust, the only things left alive will be cockroaches and Great Kiskadees.

I believe this grass to be Panicum racemosum. In spanish we call it "drawing grass" because, as you can see in the picture, it draws circular shapes in the sand when waved by the wind.

This female Shiny Cowbird posed from the back of a horse. This time of the year her brain keeps track of other species' nests, she'll have to visit them when the time is right. She is a brood parasite and will add her own eggs to these nests. After that, she won't even bother to come back, her job is done and it's the foster mother's task to raise her chicks.

A Chimango Caracara posed for the photo, it allowed us to get quite near before flying off with it's mate. This small raptor is quite common in the city and countryside, as a generalist it benefits from human presence.

The dunes are a good place for cacti, and there are two species that can get quite tall in this place. This one is a species of the genus Opuntia, the other being Cereus uruguayanus. Both have edible fruits, but you've got to be careful, this one's have nasty prickles on the outside.

This photo turned out nice, I believe this could be the invasive Senecio madagascariensis, so invasive it can grow on a tree stump.

On our way back a pair of Gray-cowled Wood-Rails showed themselves on the open road. Normally they stay to the thickets, from where they call out hysterically. It's spanish name "Chiricote" derives from it's particular calls.

To sum up, a great day enjoyed in the woods! I'll cross my fingers this can become a popular destination for bird seekers. The more visitors the more likely it will remain protected. Till next post!