Bent Oaks Rookery at Rockport

February 10th, 2022 ~ Great Blue Herons mate and nest earlier than the other herons, and they have a special home in Rockport, Texas.

Rockport Texas is about a 3-hour drive south from the west Houston area. It is blessed with not one, but two barrier islands.

In the upper map, you can see the northern portion of the long main barrier island which stretches over 500 miles from north of Galveston, south to Playa Tepehuajes in northern Mexico.

The lower map is zoomed in on Rockport and Fulton, where a second tiny barrier island provides extra protection to the inland shoreline and bay.

Four large bays and the outer barrier island near Rockport (top), and the much smaller barrier in Aransas Bay bordering Rockport (bottom).
Screenshots from Google Maps

Bent oaks leaning away from Aransas Bay at the Bent Oaks Rookery
Samsung Galaxy S10e phone photo
(Click on any photo once to enlarge in a new window; hit the Back arrow to return here.)

The Fulton-Rockport portion of the Gulf Coast is covered with ‘bent oaks’, the moniker given to Southern Live Oak trees, Quercus virginiana, stunted and shaped by the constant onshore salt-air winds. The city of Rockport includes a small stand of old-growth bent oaks. Their dense and sturdy crowns are strong enough to support large herons and egrets, and their location behind the two barrier islands means plentiful fish available within a few hundred feet.

In 2016, the City of Rockport officially designated the oak grove as the Bent Oaks Rookery Park, and provided a small parking lot. From that lot, you can see birds standing along the tops of the trees against the sky; if you zoom in on my phone photo, you can see almost 40 birds… and that is just on this side of the trees! Birders armed with cameras and binoculars have a ring-side seat to the rookery activity.

Great Blue Heron male with nice stick
1/1250 sec. f/7.1 ISO 2500
Nikon D850 with Nikkor 500mm f/5.6E PF ED VR, on tripod

Largest of the North American herons, the Great Blue Heron, Ardea Herodias, is a lovely slow-flying bird, standing roughly four feet tall, with a wingspan of over six feet. They are found throughout most of North and Central America. The soft late afternoon overcast light allowed me to focus on the texture of this bird’s feathers.

Female Great Blue Herons watch for their mates to return carrying sticks
1/1250 sec. f/7.1 ISO 2500
Nikon D850 with Nikkor 500mm f/5.6E PF ED VR, on tripod

The distance from the edge of the parking lot to the tops of the trees is around 200 ft., (as measured on Google Maps), so most of my images are significantly cropped. In the above image, you can see the dense mat of oak branches across the top of the tree, almost as if it has been hedged (hedging Live Oaks is a thing, in some gardens).

Male Great Blue Herons argue over sticks
1/1250 sec. f/7.1 ISO 3200
Nikon D850 with Nikkor 500mm f/5.6E PF ED VR, on tripod

This early in the nesting season, the ground below the trees is littered with dead branches blown and shaken down during the prior fall and winter, and competition between the males for the best sticks is just beginning. Later, as the number of nesting birds increases and the supply dwindles, there may be some real dust-ups. Several times I watched as a bird selected, hefted, and then discarded a stick, before finding the perfect one and hoisting it aloft.

Landing on tip-toes
1/1250 sec. f/7.1 ISO 2500
Nikon D850 with Nikkor 500mm f/5.6E PF ED VR, on tripod

The dim light under the trees warranted an adjustment to my ISO… which I completely ignored in my excitement over being at the Rookery. This bird’s slow landing, and the evening’s western light, showed off the layered structure of the bird’s plumage.

A stick for you, my dear
1/1250 sec. f/7.1 ISO 2500
Nikon D850 with Nikkor 500mm f/5.6E PF ED VR, on tripod

Above, a male brought a stick well over 4 feet long, to his waiting mate. This appears to be a Chinese Tallow branch, based on the attached waxy seeds. As the supply of sticks on the ground shrinks, birds may also work to break dead limbs out of the trees before they’ve fallen. You can see that some of the bare branches of this oak have been nearly plucked clean of longer sticks, through the years of nest building.

Flyover with construction lumber
1/1250 sec. f/7.1 ISO 3200
Nikon D850 with Nikkor 500mm f/5.6E PF ED VR, on tripod

The happy combination of sticks under the bent oaks means that sometimes the birds will fly very close to the parking lot (and observers!) as they circle with their building supplies to gain elevation. On this day (and most days) the prevailing wind was from the southwest; the birds were flying a big flat spiral from the ground, up, over, and around the grove, so that they could land facing into the wind.

Banked for a slow roll to the right
1/1250 sec. f/7.1 ISO 2000
Nikon D850 with Nikkor 500mm f/5.6E PF ED VR, on tripod

The Great Blue Heron breeding plumage consists of the black head plumes, cape of long silvery gray feathers along their shoulders, long creamy chest plumes, blue lores (skin around the eyes), and an orange-red bill. The touch of blue we see here in his wing tips, is, as in all blue bird feathers, the result of iridescence and reflection, not pigmentation.

I’m coming, sweetie
1/1250 sec. f/7.1 ISO 3200
Nikon D850 with Nikkor 500mm f/5.6E PF ED VR, on tripod

Bird legs and feet are analogous to those of humans… with some adjustments: what we can see here are the pink soles of his toes, and his pink heels. His knees are out of sight up close to his ribs. Bird knees bend in the same direction as human knees, toward the front.

Tricky handoff
1/1250 sec. f/7.1 ISO 3200
Nikon D850 with Nikkor 500mm f/5.6E PF ED VR, on tripod

This incoming male didn’t plan for his mate’s eagerness, as she stepped forward to receive his prize-winning stick. He landed on top of her, and windmilled his wings to keep from trampling her. He managed to hop to the side, where they worked together to incorporate the stick. This shot also shows the crowded environment in the canopy: the mated pair exchanging the stick have 3 neighboring nests, marked by the females waiting patiently for sticks. Somehow they recognize each other, and I’ve not observed any males delivering sticks to the wrong address.

Happy Valentine’s Day
1/1250 sec. f/7.1 ISO 3200
Nikon D850 with Nikkor 500mm f/5.6E PF ED VR, on tripod

Handoffs can be ungainly, efficient, or graceful. Ten minutes after the tricky handoff above, the evening sun cast a few rays of warmth under the overcast clouds, and that same pair managed a delightfully posed handoff.

Bill clattering, building a pair bond
1/1250 sec. f/7.1 ISO 3200
Nikon D850 with Nikkor 500mm f/5.6E PF ED VR, on tripod

Herons are monogamous during the breeding season (but not from one season to the next) and their behaviors include cuddling and mutual grooming activity which helps these normally solitary birds bond more strongly, assuring maximum partner cooperation during the intense period of feeding and raising up to six chicks. In the image above, the evening light caught these two clattering their bills together, a common bonding activity.

Goodnight hug
1/12560 sec. f/7.1 ISO 3200
Nikon D850 with Nikkor 500mm f/5.6E PF ED VR, on tripod

As the evening sun sank below the horizon this pair engaged in a late evening cuddle during their stick exchange. Gathering nesting materials continued as the twilight descended. It was too dark for my camera, so I just sat on my fender and watched in the chill breeze until my old eyes couldn’t see any more.

I hope to make more trips to the Bent Oaks Rookery this spring. Not only will the gangly Great Blue youngsters be growing, but the Great Egrets, pure white and almost as tall as the Great Blue Herons, will also nest in the Rookery, and watching them will be a special treat.