Excursion Report: Rainbow Beach, Great Sandy National Park, Excursion 3-5 May, 2025
Leader and Report: Greg Neill
Nineteen enthusiastic members attended the May long weekend outing based at Rainbow Beach and the Cooloola section, Great Sandy National Park. Weather on the Friday was not looking promising but all the planned activities for the excursion went ahead in mostly fine but overcast and blustery conditions. A packed itinerary took members to a wide variety of environments, rainforest, wet & dry sclerophyll forest, freshwater lakes, mangrove-lined marine foreshore, dry and wet heathland and a sand blow.
Saturday morning, we travelled to Bymien Picnic area to walk to Poona Lake. Three members walked directly to the lake. Most of us chose a longer route which involved a bit of off-track navigation through some old growth Blackbutt forest, Eucalyptus pilularis. Ron brought along his builders’ tape and measured one tree at diameter of 3.2m dbh (diameter at breast height). One observation of great interest to naturalists was located at the top of small hill cleared for a communication tower. At first glance we thought they were ant mounds with small entrance holes. However, one of our group noticed insects landing on the small sand mounds and then entering the holes. Several minutes of observations and discussion eventuated; were they bees, with large pollen sacs on hind legs, or were they wasps? The holes seemed to be deep, as the sand brought to the surface was yellow whereas the surface sand to a depth of more than 120 mm was black.
Update: After further research and iNaturalist assistance, we concluded that we had observed ground nesting bees. They have tentatively been identified as subgenus Hadrocolletes. The bees were flying around lots of nesting holes; they would land and disappear down the hole for many seconds with rear legs carrying large pollen sacs. On the excursion we only saw female bees. A few days later Annie and I re-visited the site to get some further details on the depth of the holes using a garden hand trowel. We dug to a depth of 330 mm without encountering the colored sand that the bees had extracted. On that day we only recorded male bees. Annie and I returned to the site a couple of weeks later to try and get better photos and also to record data on the size of the nesting site. The area was measured at about 104 square meters with about 200 nesting holes.
Saturday night, while some members watched the 2025 federal election, the real naturalists headed back to Bymien picnic area for spotlighting and setting up an insect sheet. Only three or four moths came into the light sheet and a couple of other insects were seen while spotlighting alongthe Bymien tracks.
Sunday morning, we went to Bullock Point to explore the sand flats and mangrove areas at low tide. Probably due to strong southerly winds the tide was not particularly low and the mud flats were not fully exposed. Undeterred, we spent an interesting couple of hours exploring the mangroves and surrounding woodlands.
After an early lunch we departed at 1pm for an exploration of the Cooloola Wilderness Trail. Another couple of hours was spent exploring the first 200 m or so of the trail. We then relocated to the Cooloola heath country to look and listen for Ground Parrots (Pezoporus wallicus). Mostly you need to wait for dusk before the parrots start up with their high-pitched whistling calls. Maybe due to the overcast and gray conditions, the birds started calling early and two of the group had beginners’ luck and got clear views and good photos of one bird sitting exposed in a small shrub.
Dinner was a group affair at the Sports Club and instead of sitting round a campfire recalling our trip highlights we discussed the day around our dinner table. Monday morning was a walk from Rainbow Beach along the Cooloola Great Walk track to Carlo sand blow. Conveniently, on the way back to town we walked past the accommodation of some of our group where we were offered morning tea/coffee. A very nice way to finish the official part of the club outing.
Some of the group who did not have to be back in Brisbane for Tuesday stayed on to the Monday. Another visit to Cooloola Plains Ground Parrot site was undertaken in the hope of more Ground Parrot views. Again, the group was successful with three members getting good photos and the non-photographers getting good sightings plus many birds calling.
Overall, a very good outing with just a lack of insects being a disappointment for those chasing invertebrates. At time of writing, the iNaturalist observations for the QNC 2025 May Great Sandy NP, Cooloola project were 603 observations of 301 species. Find the link here: https://www.inaturalist.org/projects/qnc-2025-may-great-sandy-np-cooloola