Molonglo Reach boat trip

Sun 14 February 2016 08:00am

Jack Holland

This outing/cruise will be on the upper parts of Lake Burley Griffin (East Basin) and the adjacent Molonglo River Reach, where late summer/early autumn is usually the peak time for nesting, with darters as well as three species of cormorant known to breed there. The area also has a variety of water birds, and a range of land birds can be seen on the banks.
The boat trip will last about 2 hours from 8 am and will cost $20, payable in cash on boarding. This year we will again be travelling in the electric boat “MV Gull” which can carry around 22 people. The boat allows both a quiet approach as well as access to areas difficult to get to from the land. The point of departure will again be Kingston Harbour using the wharf at the end of Giles Street. There is plenty of all day free weekend parking close by, particularly in Eastlake Parade. Alternatively participants can park their cars in the SE corner of the Glass Works/Bus Depot Markets car park, which will involve about a 200 m walk.
Registration for this field trip is essential. Please book your place on the boat with Jack Holland (on 6288 7840 AH or by email on jandaholland@bigpond.com). These trips have always been popular, so please make contact early if you want to be assured of a place.

Post event report

Under very warm but partly cloudy conditions 21 members and guests joined me for what was my seventeenth time since we started in 2003 for this now annual trip to view the darter and cormorant nesting on Molonglo Reach.  We again left from Kingston Harbour on the electric boat, the EL Gull, and first explored Jerrabomberra Creek for the short distance now possible before is blocked by a silt curtain.  We then travelled along the E bank of East Basin and into the Reach and along the S bank to the site of the new bridge before tracing our route back.

 

Lake levels were high from the good rainfall particularly in the last week of January, and with it still dry out west I had hoped this would have triggered some breeding activity.  However, we saw only one male Australasian Darter near a nest, and while it stayed there it was clearly an older and no longer occupied nest (Jim the skipper confirmed he had seen chicks in it earlier in the season).  This was the only nest seen, and altogether only 8 darters were observed on the day, in scattered positions throughout the trip.  Several of these were adult males though none of them had a significant amount of red on the neck signifying breeding plumage, and the rest seemed to be females with none of them were identified as immature birds by their dirtier and lighter plumage.

 

These numbers were half of last year’s estimate when numbers were already at an historical low, less than half the previous year’s low count, with for the first time no actual breeding observed in 14 years of leading these outings.  The reasons for this are unclear, if due to the complete clearing of the trees on the N bank in May 2008, the effect has been very slow compared with the cormorants which completely abandoned breeding on the Reach within a few years.  The building of the new bridge on Dairy Flat road is also an unlikely reason as ironically the one nest was within a few hundred metres from there.  The increased canoe and paddle board traffic remains a possible factor.

 

We saw a total of 7 Great Cormorants, generally resting on bare branches close to the water in the Reach, several with white flanks indicative of breeding plumage.  There were about 10 Little Black Cormorants and only one Little Pied Cormorant seen on the day, and no Pied Cormorants this time, though I understand up to 7 have now been counted on Jerrabomberra wetlands surveys.

 

Very limited darter/cormorant breeding has come to my attention this summer.  Mark Lintermans has confirmed that cormorants are breeding on the new Cotter Dam, as far as he can tell they are nearly all Little Pied Cormorants, with the odd Australasian Darter nesting as well.  He noted that it’s all occurring near the upstream end of the dam, and is not really visible other than by boat.  In previous years Jean Casburn has recorded breeding on the northern side of the Molonglo River downstream (W) of the Tuggeranong Parkway.  I checked there on 17 February and found around 6 Little Pied Cormorants, but access is poor and I couldn’t rule out other species being present and/or breeding.  Some must be occurring noting that Sandra Henderson posted nearly 30 Great Cormorants, quite a number in breeding plumage (as they were above), at Lake Tuggeranong on the morning of 12 February.

 

Other waterbird activity on the creek, river and East Basin consisted mainly of common species seen on the open water and on the banks, with the highlight being a pair of Chestnut Teal which we nearly overlooked because the male was in its much duller non-breeding plumage.  This is only the third time we have observed this species more associated with brackish waters/coastal lagoons etc, with a similarly rather dull male seen a year ago and a pair in January 2006.  A Latham’s Snipe was seen by just a few on the bank of East Basin and 3 Greylag Geese were seen in the water close to where they were seen on the previous 3 trips.  Land birds also consisted of mainly common species with the highlights being a total of 8 Dollarbirds, often in pairs along the route (certainly the most we’ve ever seen on this trip), and 4 Sacred Kingfishers.

 

At 48 the total number of species was similar to previous years, but with this time the species total from Molonglo Reach much the same as those from Jerrabomberra Creek and the East Bank.  Despite the lack of darters/cormorants breeding participants again enjoyed the trip which remains a popular late summer outing, and I propose to run it again at the same time in 2017.  Who knows the darter/cormorant breeding may come back, or at least it will further confirm that the 10 years or so of significant breeding on Molonglo Reach is now over.

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