A full complement joined me on the MV Darter on a breezy though sunny autumn late afternoon to investigate cormorant nesting activity. And in respect of Little Black Cormorants no-one could have been disappointed as we saw an estimated 150 of this species, with close to 75% of these in a stretch of about 50 metres only a few hundred metres west of the Sullivan's Creek bridge. These were spaced out over 4-5 large but quite dead trees, and closer inspection revealed a large number (over 30) nests, all of which had birds sitting on them, except for one which contained several relatively large chicks. This was repeated but on a much smaller scale several times further on. However, no birds were apparent at the relatively open spot closest to the bike path.
In total 40 nests with birds sitting were seen, but only the single nest with young. This is both the most birds and the most nests (about double the previous highest) of this species seen in COG trips now spanning over five years. The obvious questions to ask are why the nesting was still at such an apparently early stage (we had strong evidence that there were still eggs in at least some of the nests), and what will be the success rate with winter only just around the corner? Perhaps the three weeks of warm weather in the first part of March triggered this. While this is pure conjecture, Jim the skipper noted he had seen very few of this species here before then. From previous COG trips we know that nesting of Darters continues right until the end of May, though cormorants usually finish breeding well before this.
Interspersed with their smaller cousins at the first spot were about half a dozen Great Cormorants, one nest with chicks close to fledging, and the other with a bird still sitting. About a dozen Darters were also seen in singles or twos spread most of the way along, but in complete contrast to the Molonglo River two weeks before we observed no breeding activity. All except two were in female or immature plumage, with the males only seen at the very bottom of the peninsula. Great views were had by all of several Darters in the water, snaking along with body fully submerged. This was also the spot where we saw the lone Little Pied Cormorant, which obligingly stayed on a dead log long enough for all participants to get good looks at its diagnostic features.
As for the Molonglo, water birds were relatively scarce, though we did manage to see one Eurasian Coot this time, with the skipper confirming they seem to have disappeared off the lake for the past year or so. A bit of a surprise was a male Chestnut Teal consorting with some Pacific Black Ducks. Land birds were also relatively scarce, with the undoubted highlight being good views of a very late Sacred Kingfisher as we sailed past Spinnaker Island on the way home.
A smallish egret flew over (and back) close to disembarkation. Most identified it as a Cattle Egret, but there were some powerful views that it was a Little Egret. All participants agreed it was a very pleasant way to spend a reasonably balmy autumn evening. Certainly both the Black Mountain Peninsula and the Molonglo now seem to be firmly entrenched as significant annual Darter/cormorant breeding spots, with late summer/autumn the peak breeding time.
Jack Holland