Nature News: Baltimore orioles are here for our bugs

published May 25th in and the Portsmouth Herald, York Weekly, Foster’s Daily etc

Male baltimore oriole Steve Morello photo/

Our woods are starting to get extremely buggy, so much so I was thinking about ways to kill off mosquito and black fly larvae. I mentioned this to my son and was, luckily, brought back to my senses by his reply–”what about the birds?”.  We do have extremely buggy springs and summers, this is the reason many birds (neotropical migratory birds) migrate up from the tropics to breed in our forests.  They escape the competitive pressures of the tropics (so many species competing for the same resources) and instead spend the energetic capital to come up here where there are fewer competitors and tons of insects and fruit.  They don’t overwinter because the supply of food (insects and fruit) diminishes to unsustainable levels in the fall and winter.  So, I decided not to buy some mosquito dunks to toss into my ponds and let nature take its course.

Female oriole Steve Morello photo

One of the flashiest neotropical migrants nesting in our backyard this year is a pair of orioles.  I love these birds-they have a beautiful melodic song, weave intricate, pendulous nests and are so colorful.  The males are resplendent orange and black, while the females and juveniles are a lovely yellow with some orange patches on the breast, gray on the head and back, with two obvious white wing bars (the males only have one).  They are sturdy birds with long pointed bills-resembling the other members of their family-the blackbirds and meadowlarks. Knowing this relationship makes it easier for me to identify their call–it has that burbling quality of a meadowlark’s call.  We put out oranges at the feeder, along with some grape jelly, and they visit, scooping up brilliant globs of jelly that glow in the sunlight. 

This dates me a bit, but I always have to consult my most recent bird book about their name.  I remember when this species was combined with the Bullock’s oriole into one species called the northern oriole because there was so much hybridization where their ranges overlapped in the Great Plains.  Then, back in the 1990s (seems like yesterday), genetic studies determined that they are, in fact, two separate species and so they were given their old names back. 

My favorite thing about orioles, and perhaps the thing they are most famous for, is their nest-a dangling sock-like structure.  I’ve been looking around for the nest but haven’t found it yet–I thought they always dangled from a branch but this isn’t  true, sometimes the nest is anchored to the trunk of a tree.   The females are the weavers, constructing their nests in three stages.  First, the outer dangling sock, which she begins by looping long flexible fibers (grasses, bark, wool, old string or fishing line) over a tree branch and then pushing her bill through the fibers which tangles them and creates knots.  While random in nature these knots form a decidedly strong woven nest.  She’ll do one side first and often works from inside the bowl to shape the rest of the nest. She then adds springy fibers to give more support to the inner bowl and finally soft materials and feathers to line the bowl. (Cornell Laboratory of Ornithology).  It generally takes about one week to construct the nest.

While Baltimore orioles are certainly attracted to fruit and sugary liquids (like jelly or the hummingbird feeder) while raising young the majority of their diet are insects which provide the protein needed for growth.  In the fall and spring, before and during migration, their diet shifts to mostly ripe fruit and nectar-these provide the high energy sugars needed for the rigors of migration. 

If you want Baltimore orioles and other neotropical migrants (warblers, tanagers, etc)  in your backyard, don’t use pesticides.  Insecticides kill insects-essential prey for our migratory birds. Remember, the reason migratory birds come here isn’t to visit us, it is for our bugs.