Jun 14, 2012

Is that oil or algae?

Photo by Ron Fulks. More photos HERE.


This week, a group of red-throated loons in Pillar Point Harbor caused some concern from local conservationists and birders - the loons appeared oiled.

Although the substance looked very similar to oil, WildRescue's director, Rebecca Dmytryk, determined it was algae. This was confirmed by oiled wildlife expert, Jay Holcomb, with International Bird Rescue.

It is not uncommon to find aquatic birds, such as loons and grebes, in still waters of a marsh or harbor, with patches of algae on them. These are typically birds that are not fairing well for one reason or another, and they have come to the quiet waters to rest.

To confirm the sightings, our Half Moon Bay responders, Jeff and Jessica, volunteered their time to have a look. Here is what they found:



The affected birds seemed very troubled by their condition, and were preening almost obsessively. But it looks like it is mostly on the outer edges of their features. And they seem to be floating just fine.

In terms of birds that were affected by the algae, here is what we saw in that area of the harbor:


- Common Loon - One that appeared to be about half way through its molt into alternate plumage - had the black substance on it fairly heavily and preening quite a bit. But it also successfully dove and caught fish.


- Pacific Loon - One in alternate plumage with the black substance. Also preening quite a bit.


- Red-Throated Loons - There were a handful - probably 6 (not 14). I’m not sure if they are really juvenile’s…or adults that have not molted into the alternate plumage. The latter could make sense if they are sick birds and don’t have the energy to accomplish the molt. Their feathers generally seemed to be fairly worn. The primaries appeared to be so worn on some birds that I question whether they could fly. Of the Red-throated’s that were there, about half showed obvious signs of the black substance, the other half did not.


- Red-breasted Merganser - one female standing on the rocks and preening. Black substance on some features and seemed to be on feet as well.


- Surf Scoters - A female and male that appeared to have the black substance and feathers that were sticking together, as well as a black gloss to their feet (that would otherwise be pretty bright orange).


In addition to these birds, there was a small Scoter flock that appeared to be perfectly healthy. And also a handful of Mergansers that also looked fine.

Many, many thanks for those who reported the birds, and to Jeff and Jessica for taking the afternoon to do a thorough check for ailing birds.