When Clark’s Grebes and Western Grebes Walk on Water – The Courtship Behavior of Rushing Grebes

I am making a concerted effort this spring to photograph the rushing behavior of Clark’s Grebes (Aechmophorus clarkii) and Western Grebes (Aechmophorus occidentalis). I have seen plenty of grebes “walking on water” (rushing) as part of their elaborate array of courtship behaviors and have wanted to produce really top quality images of this spectacular behavior.  In particular, this year I am trying to make uncropped** highly-detailed images of fully upright grebes rushing side-by-side perfectly lit by sun at my back as well as in silhouette with the sun illuminating all the droplets of water from behind.  I want good images illustrating the “dip-shaking” and “ratchet-pointing” behaviors the bird pairs usually exhibit in association with rushing.  And I want top-quality images of mixed-species rushes in which a Western Grebe and a Clark’s Grebe pair off and rush together even though they are technically different species (albeit quite similar and occasionally interbreeding).

**I will add that one of the challenges here is self-imposed: I do not crop my images much. This is a disadvantage if I compare my images to others as much bird photography on social media is cropped severely in order to make the subject large in the frame.  I have a different approach and prefer to produce richly detailed high-resolution images suitable for big printing or display. Severe cropping also lessens the publication potential of the image, not a concern to most photographers in this day of dwindling magazine and calendar markets but I still pursue editorial publication of my work and have to keep that in mind.  The result is that I need to hand-hold a giant lens on a small boat and wait for those occasions, sometimes few, when the behavior for which I am looking occurs close enough to my boat that it fills the frame of the camera naturally.

When grebes “walk on water” it is known as “rushing”. Roughly speaking (I am not a bird expert or wildlife biologist), rushing among grebes is a courtship behavior, observed early in a breeding season when solitary grebes are seeking a mate as well as between established nesting pairs as the season continues. My belief is that there is a competitive element to it as if two grebes are attempting to impress one another or prove their prowess to a prospective mate while competing with a group of courting candidates.  When grebes rush, they typically first meet and execute “dip-shaking”  and/or “ratchet-pointing”.  Both of these behaviors occur with the birds facing one another, sometimes so close that their beaks nearly touch.  Dip-shaking involves one bird dipping its beak or head into the water then lifting it out of the water and shaking it, throwing water about.  One bird observes the other dip-shaking, then the roles are reversed.  Ratchet-pointing involves both birds assuming a very low posture in the water, pointing their beaks at one another and appearing to look each other in the eye, perhaps raising their crests and often emitting a ratchet-like vocalization.  Several rounds of dip-shaking and ratchet-pointing may occur, each lasting a few seconds.  It seems to me the birds are communicating something and in the process deciding whether they will rush or not.

The prelude behaviors of ratchet-pointing and dip-shaking serve as “tells” that a rush may be imminent. Rushing doesn’t always occur — sometimes the birds simply pair off and swim calmly away after ratchet-pointing.  But when they do rush, it usually follows some incarnation of those two prelude activities.  When they suddenly erupt from the water into a rush, they synchronously propel themselves forward and up with an extremely rapid beat of their webbed feet, up to 20 beats per second.  Side-by-side they run across the water for as long as 6-7 seconds and 60 feet (20m) before settling back down into the water.

One can watch grebes and will surely, eventually, learn to hear the vocalizations and spot ratchet-pointing and dip-shaking.  I am however rather slow when it comes to birds so I sought help, spending several mornings out on the lakes near my home in San Diego over the past few years with Brian Caldwell. Brian is a skilled and fun professional guide and photographer who lives near Lake Hodges and has been studying the natural history of these grebes for many years.  He is also highly knowledgable about the environmental issues, especially the topic of water use in San Diego’s reservoirs, a surprisingly complex subject, that impact the grebes and their ability to nest and rear young. If you want to photograph these birds and have never done so, Brian can improve your odds of success immensely.  In addition to leaning on Brian’s guiding, I have spent quite a few mornings alone in a small boat looking for glassy water, good early light and courting birds in an effort to produce good images.  It’s a tranquil way to start the day.  Here are some of my favorites of this year’s efforts.  Cheers, and thanks for looking!