Birds

Wildlife Wednesday: Spring Migration

Wildlife Wednesday: Spring Migration

When people think of Spring migration, they usually think of bird migration. During Spring Migration, we see wood warblers, orioles, tanagers, buntings, thrushes, and other birds, returning from the neo-tropics (Central and South America) to their breeding grounds in North America. We refer to birds from temperate regions of North America, who overwinter in tropical America to the South of us as “Neotropical Migrants.”

Bird migration is well known, but what many may not know is that various species of butterfly and dragonfly also migrate South in the Fall, and return North in the Spring. Here’s a look at 3 species of migrants that pass through the park every Spring.

  

Photographs via: U.S. Fish & Wildlife Service and National Park Service

Prothonotary Warblers (Protonotaria citrea) are bright citron yellow wood-warblers that nest in tree cavities, unlike most other species of warbler, which make more typical nests out of vegetation on tree branches. However, like most new world warbler species, they feed mainly on insects and other small invertebrates (caterpillars are an especially popular food item). These birds are usually associated with forested wetlands (swamps), where they nest and feed. During the breeding season, they’re found in the Eastern U.S. and SE Canada, and they overwinter in Northern South America, and the central Caribbean coast of Mexico. They are found nesting in swamps East and North of the Houston area, but we only get them in Russ Pitman Park during Spring Migration.

  

photographs: Dan Mullen | Flickr, Jim McCulloch | Flickr, and Henry Hartley | Wikimedia

Green Darners (Anax junius) are large dragonflies that leave their breeding grounds across North America to migrate South for the winter to Texas and Mexico. This is an exceptionally wide spread and common species of dragonfly, found breeding and feeding around still bodies of freshwater (mainly lakes, ponds, marshes, and swamps). They are highly predatory, taking wasps, spiders, butterflies, and even other dragonflies (including other Green Darners, at times). Large numbers of them are noticeable during fall migration, and they return to their breeding grounds during spring migration (though this late stage of the adult life cycle, and migration habits and patterns are not well studied nor well understood). Most species of dragonfly in North America do not migrate seasonally like this, but instead die off in the fall (leaving behind aquatic offspring to overwinter).

  

Photographs via: U.S. Fish & Wildlife Service and National Park Service

Monarch Butterflies (Danaus plexipus) are famously migratory butterflies, overwintering in mountain forests in Northern Mexico. They return to the U.S. in April, and undergo an annual migration cycle that is completed over 4 generations (with no single individual completing the entire migration cycle). Their geographic distribution and patterns of movement are actually somewhat complex, as a population, but here is a simplified overview of their migration.

Generation 1 hatches out in the Southern U.S., migrates to the Central U.S. then mates and dies.
Generation 2 hatches out in the Central U.S., migrates further north, then mates and dies.
Generation 3 hatches out in the North, migrates further North, then mates and dies.

Generation 4 hatches out in the far North, and then undertakes the longest leg of the migration, spending the Autumn migrating 1000s of miles back through the U.S. and down to Mexico, where they will spend the winter. In the Spring, they will migrate back to the Southern U.S., where they will mate, lay eggs, and die.

Meadows, wildflower gardens, and prairie are very important to Monarchs while migrating, as they will only lay their eggs on Milkweeds (genus Asclepias), which are found in these habitats.

Sometime this April, head out to the Nature Discovery Center, and see if you can spot one or all 3 of these Spring Migrants. If you’re interested in learning about more species of migrating birds, dragonflies, and butterflies, ask one of our helpful naturalists on site or feel free to email me with questions.

Thanks and see you soon!

Eric Duran
Staff Naturalist

Top photo of male Blackburnian Warbler by Laura Gooch | Flickr

Read more

Wildlife Wednesday: Birds Nesting in the Park

Wildlife Wednesday:  Birds Nesting in the Park

Spring is a time when flowers bloom, deciduous trees re-leaf, and the insects emerge from their winter hiding places. It’s also the time of year when we notice birds nesting and laying eggs. Today, during our hikes with students and birdwatchers, we noticed 3 sets of birds nesting in the park.

Eastern Screech Owls (Megascops asio) actually started nesting here in mid-winter, as they have for several years. Owls have to train their young to hunt, so they start the process of nesting earlier than other groups of birds, so they can spend more time getting them ready to live out in the world on their own. Our owls are most likely deep into the process of incubating eggs. Screech Owls are small, and a eat a wide variety of smaller animals (such as small snakes, lizards, birds, large insects, and spiders). In the evenings, you may hear them singing soft trills, whinnies, and less commonly, screeches, from the trees around the park.

They nest in tree cavities, like abandoned woodpecker holes and hollow branches. In our park, they raise their young in nest boxes, made specifically for them. We currently have 3 pairs of nesting Screech Owls in the park, and with 2-4 young per nest, we could end up with 12 young owlets fledging out this year!

Cooper’s Hawks (Accipiter cooperii) have been nesting in the park for 3 seasons now. These thin agile hawks, specialize in hunting other birds in wooded areas. You can often see them sitting on a tree branch, pulling apart and eating a White-winged Dove or an American Robin. They are also conspicuous by their call, a loud high pitched KEK KEK KEK KEK KEK KEK KEK echoing out through the canopy of the trees.

They start courting and mating in late winter, and construct their stick nest high in a tree in late winter/early spring. It appears that the Cooper’s Hawk pair in our park have finished their nest, and are now incubating eggs.

Finally… the Purple Martins (Progne subis) have returned to Russ Pitman Park! We did see a few, here and there, in mid-February, flying over the park, but this week we noticed them returning to the colonial Purple Martin house next to the playground. They appear to be entering the nest holes and setting up shop. So far we have seen 3 pairs of North America’s largest swallows here. Today (3/22) they were very active, fluttering above the South end of the park, singing and catching insects on the wing. Purple martins are active and able hunters of dragonflies, flying grasshoppers, and other insects that go high up into the air.

We invite you to come out, and look for all 3 species in the park. If you need help finding them, a helpful naturalist can give you direction.

Thanks, and see you soon!

Eric Duran
Staff Naturalist

Above Photos: Screech owls by Roland Groenenboom, Cooper’s Hawk by Don Jewell, Purple Martin by JJ Cadiz | Wikimedia

   

photo by Teresa Connell                                        Photo by Sean Sun                                      Photo by Mike Carlo, USFWS              

Read more