Flashing wings as a hunting technique

Northern mockingbird IMG_2475©Maria de Bruyn resLast year, during a nature walk, I witnessed young Northern mockingbirds (Mimus polyglottos) displaying odd behavior as they strutted around on the ground. They would walk and hop a bit and then suddenly spread their wings wide and wider still, then close them and continue pecking on the ground.

Some research on the Internet revealed that they were engaged in a phenomenon known as wing flashing. There are various theories about why mockingbirds flash their wings -– to startle insects, ward off predators, attract a mate. So far, there is no scientific consensus on why they do this.

Northern mockingbird IMG_8889©Maria de BruynresNorthern mockingbird IMG_8904©Maria de Bruynres

Having seen both adult and juvenile birds performing this behavior again this year, however, I’ve become convinced it is part of their hunting technique. Those who promote this idea have suggested that the sudden appearance of the bird’s white wing-bars startles insects, but others argue that insects are not alarmed by the color white.

Northern mockingbird IMG_2816©Maria de Bruyn res

Northern mockingbird IMG_2604©Maria de Bruyn res

My own theory is that when the mockingbirds flash their wings, it creates air currents and disturbs the grasses, thereby uncovering and rustling up bugs. This year I clearly saw the birds catching and consuming insects just after a completed wing flash.

snowy egret IMG_3610© Maria de Bruyn

Later in the summer, I witnessed a similar kind of wing flashing used as a hunting technique by an entirely different species, the snowy egret (Egretta thula). These elegant white birds have long black legs ending in feet that look like they are covered with yellow rubber gloves. They stalk the shallows of waterways such as marshes and ponds looking for prey. The bird I saw was fishing in tidal pools along the Atlantic Ocean shore.

snowy egret IMG_3286© Maria de Bruyn

snowy egret IMG_3270© Maria de Bruyn

It is thought that the egrets use their large feet to stir up the sand underwater so that they can more easily see potential food as they forage. Part of the time, they will simply stand like statues, waiting for a fish to swim nearby so that they can suddenly plunge their long beaks into the water to get their meal.

snowy egret IMG_3313©Maria de BruynThis worked at least part of the time for this particular bird, as s/he got a few fish down. It required a lot of patience, however.

snowy egret IMG_3423© Maria de Bruyn res

At a certain point, the bird decided on a more active approach. S/he flew to another tidal pool and then began running to and fro in the water, flapping his/her wings open and closed.

snowy egret IMG_3575© Maria de Bruynsnowy egret IMG_3574© Maria de Bruyn

Occasionally, this was complemented by a leap into the air and plunge into the water – obviously behavior calculated to startle and scare up the fish lurking below the water’s surface.

snowy egret IMG_3606© Maria de Bruynsnowy egret IMG_3617© Maria de Bruyn

snowy egret IMG_3623© Maria de BruynThe tactic worked.

It was fascinating for me to see two such different bird species using their wings in a similar fashion as a hunting method. One of the things I love about wildlife watching -– you can always see and learn something new!

snowy egret IMG_3659© Maria de Bruyn

My love affair, take 2

osprey IMG_0689© Maria de Bruyn res

The ospreys (Pandion haliaetus) continue to capture my heart, even though my numerous forays to lakes and ponds to get some excellent photos of them have not yet paid off. I finished the book on osprey migration, Soaring with Fidel, and thoroughly enjoyed it.

Reading about different birds’ personalities and choices for migration was really interesting; learning about the different people who dedicate their lives to learning and sharing information about ospreys kept my interest, too. The ospreys definitely have a devoted fan base.

It’s quite amazing to think of these birds flying several thousand miles within a short period of time so that they can spend the winters in warmer Caribbean and South American climes. When I was at Topsail Island, I was lucky to see a few ospreys that were apparently on their migratory journeys. They flew very far overhead, but I did see one drop down into the ocean and come up with a meal.

osprey IMG_4103© Maria de Bruyn resosprey IMG_3810© Maria de Bruyn

 

One day when I was at North Carolina’s largest man-made lake, Jordan Lake, I was lucky to see an osprey begin a predatory dive that was a bit nearer to me than usual.

osprey IMG_0805© Maria de Bruyn res

The bird’s wings and claws were spread as it readied itself to grasp the fish that was in sight down below.

osprey IMG_0803© Maria de Bruynosprey IMG_0802© Maria de Bruyn

osprey IMG_0806© Maria de Bruyn resSometimes the birds will face forward to dive down and then flip upwards at the last minute so they enter the water feet first. This bird did most of the dive with its feet down in the clutching position, ready to strike.

osprey IMG_0812©Maria de Bruyn res

A mighty plunge!

osprey IMG_0813© Maria de Bruyn resAnd then emergence with a meal caught in those feet with unique reversible back toes to help the osprey hold on to the slippery fish.

osprey IMG_0815© Maria de Bruyn resThis was a happy bird. And when another (or the same?) bird suddenly flew right over my head to grace me with a piercing gaze, I was a happy birder!

osprey IMG_0736© Maria de Bruyn res