We have cormorants drop in to fish in the dam every now and again. Mostly, they come on their own, but sometimes they bring a friend or two. In the months leading up to Christmas, I was much more drawn to the herons, ducks, and more exotic species of bird, paying little attention to the cormorants other than to note if they were there or not. So, when they stopped coming for a few months over Summer, it surprised me that I missed the sight of outstretched drying wings on the end of the jetty.
In the last couple of weeks, one cormorant has returned. While it is pied in colour, it seemed starkly white and jet black instead of the muddy white and brownish black of the pied cormorant we’d had before. This prompted me to dig out the field guide to Australian birds and have a closer look at the various cormorant species. Potentially, four species of cormorant are found in our area – The Great Cormorant, the Little Black Cormorant, the Pied Cormorant, and the Little Pied Cormorant. Each species has breeding plumage that varies from their non-breeding plumage. This makes it a little tricky to work out exactly which species we have had here, but I will do my best to sort it out.
First I’ll look at the pied coloured cormorants. From the descriptions in the field guides, it seems that immature birds have muddier colouring than adult birds. This occurs for both the Pied Cormorant and the Little Pied Cormorant, so it is possible that the same cormorant has returned, now with adult plumage. The next step is to work out if they are Pied Cormorants or Little Pied Cormorants.
Size and bill colour are the clues here. Little Pied Cormorants are approximately 58 – 64 cm in length. We have a white measuring rod on the end of the jetty to measure water depth in the dam. Seven inches of this stick (17.5 cm) are above the handrail, giving a good indication of the size of the cormorant. It is too small to be Pied Cormorant, which reaches 66 – 80cm in length. Also, Pied Cormorants have a bill that is more bone coloured, and Little Pied Cormorants have yellow on the side of their bill. I think it is safe to say we have Little Pied Cormorants visiting us.
Now to the black cormorants. This is more difficult to resolve. The size difference between the Great Cormorant and the Little Black Cormorant is similar – Little Black Cormorant 58 – 64 cm and the Great Cormorant 72 – 92 cm in length. The Great Cormorant has a yellow ochre coloured throat patch and horn coloured bill, while the Little Black Cormorant has a black bill, and no yellow markings. Both species have fine white streaks on their neck feathers when in breeding plumage, and the Little Black Cormorant also has a bronzed appearance while displaying breeding plumage.
From the photographs I have taken, I believe we have had both species here.
If I’m identifying these birds correctly, we have had three of the possible four species of cormorants here. Over the next few weeks I will write a post on each one, including more photos of each species.