Me with a Yellow-breasted Flowerpecker (Prionochilus maculatus) captured during mist-netting surveys at Danum Valley, Borneo.
A Diary of a Naturalist, by Jasmin Knight
I’m a 22-year-old Australian hobbyist wildlife photographer and student of Marine Biology and Zoology at James Cook University, Townsville.
All photos are taken with my Sony a6300 and 55–210mm lens.
I’m learning the science of the natural world and the art (and science) of photography — documenting my journey as a growing scientist, photographer, and writer.
The Australian King Parrot shows strong sexual dimorphism, with vivid red males and mostly green females. Their differences were once so convincing that British naturalists believed they were two separate species.
Black flying fox (Pteropus alecto), Townsville, Australia.
I have been very busy and a little sad since leaving Danjugan Island, so I have not had much time to post. Now that I am finally going through my photos, I will start sharing my remaining Danjugan Island field notes, some Australian wildlife, and a few photos from my time in Danum Valley, Borneo.
I feel like I’m getting better at editing. I haven’t watched any tutorials; I’ve just been pressing buttons in Lightroom and hoping for the best. Maybe that’s the real way to learn.
The dog-faced pufferfish is also known as the black-spotted puffer, but I prefer the first name because they really do look like little dogs or seals.
These pufferfish can change colour depending on their mood, environment, and stress levels. They occur in several colour morphs: yellow, grey, mottled, or almost completely black. They can shift shades to blend into their surroundings or signal agitation.
This individual was being cleaned by a Blue-streak Cleaner Wrasse (Labroides dimidiatus), which removes parasites and dead tissue from other fish. Cleaner wrasses are surprisingly intelligent and can even remember individual clients, adjusting their cleaning behaviour based on past interactions.
The Asian Koel (Eudynamys scolopaceus), Danjugan Island, Philippines
Male Asian Koel feeding in a Ficus microcarpa tree.
Asian Koels are sexually dimorphic, meaning males and females look markedly different.
The female is brown with heavy white spotting and streaking, and she has a barred tail. She is usually quieter and much harder to spot.
The Asian Koel is a brood parasite. The female lays her eggs in the nests of other bird species, most commonly crows. The host parents raise the koel chick as their own, even though the chicks grow much larger than their foster parents and often outcompete their nest-mates.
Stork-billed Kingfisher (Pelargopsis capensis), Danjugan Island, Philippines
I said I wouldn’t leave the island without at least one photo of a Stork-billed Kingfisher. I had seen them many times, always flying away before I could lift my camera, and I was never quick enough to get a decent shot. Luckily, I was fast enough the other day to get this photo. Unfortunately, I was not fast enough to get a clear one, so please enjoy this gloriously blurry photo. I am leaving the island today, so I am glad I at least have proof that I have seen this species.
Stork-billed Kingfishers have one of the loudest calls of all kingfishers, a sharp, ringing laugh that echoes across rivers and mangroves. Their oversized red bill is not just for show; it helps them catch fish, crabs, and even small reptiles.
Golden-bellied Gerygone (Gerygone sulphurea) field notes: roosting behaviour and possible post-fledgling association
Link to Pt.3: https://www.tumblr.com/adiaryofanaturalist/800141836021809152/on-the-golden-bellied-gerygones-pt-3
💬 0 🔁 0 ❤️ 2 · On the Golden-bellied Gerygones, Pt. 3 · Golden-bellied Gerygones (Gerygone sulphurea) roosting at dusk.
Link to part 2: h
Observations
First sighting — 27 October
- Observed two individuals singing and settling to roost in a Pongamia pinnata tree.
- Clear size difference: one bird was significantly smaller and fluffier, with mottled underparts compared to a uniform yellow.
- Larger bird settled first and the smaller one followed
- Both individuals remained in close proximity at dusk and later in the night.
Second sighting — 12 November (post-typhoon)
- Pair observed again in the same tree.
- Smaller bird settled first this time
- Size difference still visible but reduced.
Third sighting — 13 November
- Both birds present at the same evening roost site.
Fourth sighting — 26 November
- Both birds again returned to the same tree at dusk.
- At this stage, the two individuals are much more similar in size, making identification of the smaller bird less certain.
Fifth Sighting- 28 November
- No notes
Sixth Sighting- 30 November
- One Gerygone has a paler brown plumage on shoulders and wings than the other
Additional notes
- The birds were recorded roosting in the same tree on multiple nights, although continuous monitoring was not possible due to time away from the island.
- No other gerygones were observed near the roosting tree during these periods.
- No active nest located in the immediate area (to my knowledge)
Interpretation (tentative)
- The initial morphological differences and close evening association suggest a possible parent–fledgling pair, particularly during the first late-October sighting.
- Continued evening association into late November is consistent with extended parental care, though not confirmatory.
- The reduction in size differences by late November is expected if one individual was a fledgling undergoing growth.
Context from Literature (used for comparison only)
- Golden-bellied Gerygones breed mainly March–September, but on islands, in mangroves, and in equatorial climates, the breeding window may extend into October or November (source: regional field guides, Birds of the World).
- In a close congener, the Grey Warbler (Gerygone igata), fledglings are fed by adults for 28–35 days after leaving the nest (Gill 1983), demonstrating prolonged post-fledging parental care in the genus.
- A study on fledgling discrimination in Hoopoes notes that the post-fledging period is one of the least studied parts of avian life history (Gruebler & Naef-Daenzer 2010; Matthysen et al. 2010), highlighting the general lack of data for similar small passerines.
- Literature on night-time roosting behaviour in Golden-bellied Gerygone or closely related species is extremely limited.
- Within Acanthizidae (same family), some species such as the Yellow-rumped Thornbill use specific roosting structures, and in some cases males have been noted roosting near fledglings (source: field observations), though this behaviour is not documented in Gerygone sulphurea.
- Golden-bellied Gerygone is known to exhibit biparental care during the nestling phase, based on limited species-specific accounts and analogy with well-studied congeners.
Other Notes
Further observation, especially of morning activity or feeding behaviour, would be necessary to clarify the relationship between the two individuals.
Nankeen Night Herons have been observed dropping insects, feathers, leaves, or even bits of bread onto the water surface to lure fish closer, one of the few birds known to use tools in hunting.
Most animals get their colours from pigments; chemicals inside their skin or feathers that absorb some wavelengths of light and reflect others (like paint). But the male Pink-necked Green Pigeon is different.
The bright pink, purple, and green you see aren’t created by pigment. Instead, the feathers have tiny microscopic layers arranged in very precise patterns.
These layers bend, scatter, and reflect light in different ways depending on the angle. This creates a glowing, shimmering effect called structural colouration. This optical interference produces high-intensity, angle-dependent colours, similar to iridescence seen in butterflies and soap films.
Female Pink-necked Green Pigeons are predominantly olive-green with a yellowish belly and lack the male’s bright pink and purple patches.
I was promised I would see a coconut crab, and I did not believe them. Vince and I went looking a couple of nights and saw many coconuts, many crabs, but no coconut crabs. I was starting to think they had been harvested for food by illegal poachers who could have trespassed on the island. They have very slow reproduction and are considered Vulnerable worldwide. I am very lucky to have seen this juvenile coconut crab.
Here is a list of fun facts because there are so many:
• Coconut crabs are the largest land-dwelling arthropods on Earth.
• They are capable of cracking bones to reach marrow.
• Adults can weigh up to 4 kg and reach a 1 metre leg span.
• They can lift objects up to 30 kg.
• They climb trees to steal coconuts, drop them, and smash them open using their claws.
• They navigate long distances by smell, using olfaction more similar to insects than to other crabs.
• Females migrate to the coastline to release eggs into the ocean.
• Larvae spend 3 to 4 weeks drifting in the plankton before settling.
• Juveniles wear snail shells for years before outgrowing them.
• They store coconut-oil-like fat that can be unusually flammable.
• They sometimes gather in groups to scavenge large carcasses (they possibly ate Amelia Earhart).
• They line their burrows with fibrous coconut husk to retain moisture.
• They are surprisingly smart and capable of opening complicated latches and containers.
• They mainly eat fallen fruit, nuts and seeds, carrion, baby sea turtles, ground-nesting birds, other crabs, and possibly Amelia Earhart.
I gave the kittens away to their new owner yesterday, and I can’t stop thinking about them. I cried so hard leaving them. I spent three days with them, sleeping on the hard floor with them to the demise of my lower back, and they really got attached to me and I to them. I wish I could take them back to Australia, but it would be roughly $20,000 and a six-month to one-year process. They can’t understand why I’ve left, and I can’t tell them. It breaks my heart and makes me feel sick.
I feel that finding kittens on the side of the road is the cat equivalent of giving birth to a human child. They looked at me with so much trust, like I was their mother. They’ve already been abandoned once, and I abandoned them again. I can’t see that I’ve done something good, because I just feel so terrible.
I have to hug myself like they are sleeping on my chest when I feel sad. I imagine their weight on me when I go to sleep. I feel like I’ve given away my babies. My blood-born children.
