I love the outdoors and since we have lived in Broome I have spent a fair bit of time walking and cycling our beautiful Cable Beach. In 2000 I discovered a Pied Oystercatcher nest site, which was not hard for the observant observer due to the fact that they walk away to distract you, leaving a trail….all footprints lead to one area. Over the years the birds have moved their nest site a few hundred metres as a result of human traffic and dogs, but they have been consistent.
As I had more time available I decided to monitor a longer stretch of beach, as no research had been done into the breeding of Pied Oystercatchers in the north of Australia. They breed from July to November in the north due to the weather, which is much nicer weather for us to enjoy the beaches as well!
Three years ago I made the commitment to cover a 23km stretch of beach on a regular basis during the breeding season on foot and by bicycle. I have 16 pairs of birds and all nest records are submitted to Birds Australia nest record scheme. Any other nests that I come across are also reported and this has been Red-capped Plovers most commonly. Several of the Pied Oystercatchers are individually marked and for the first time this year I found a female had given up her territory after 10 years to partner with a male 3kms further south. By coincidence they were banded together in 2002, so they knew each other! I have a bird that is at least 21 years old. The birds take it in turns sitting on the eggs (almost always two eggs here) for 28 days and once the hatching is imminent they will both be there. The chick will bond with the bird that is sitting when it breaks free regardless of sex.
The saddest thing I have had to deal with is the constant predation of eggs by feral cats and the birds attempting to breed three or four times in a season. Down south the predators’ footprints are not always visible, but foxes and cats are a problem throughout Australia. This is not just a household size cat, but a larger version and they have been a problem in Australia for over 100 years. Over 50 eggs were predated last year. It is only the longevity of this species that gives us hope that there will not be a decline in population here, though it has been listed as “endangered” in New South Wales.
All of the Pied Oystercatchers are silent and walk away from their nests until the chicks have hatched and then they call out a warning signal to the chicks. If you sit quietly they will change their call to alert the chick that it is safe and they will appear from their hiding spot. Each chick has individual markings on its back. The most amazing thing to watch is them teaching their chicks about the 10 metre tides. They encourage them to follow by swimming to get to the reef within a couple of days of hatching and they will dive if a predator passes over.
The chicks grow incredibly fast and will increase from 30 grams to 300 grams in a month. Their feathers develop a lot faster here than down south and they learn to fly earlier, most likely as they don’t need to put any energy into keeping warm in this environment!
All birds on the beaches need to hide and in desperation this Red-capped Plover took shelter in a footprint, as the tide was out and there really was nowhere else!
Now for that “non-bird” photo….this time it’s the DEADLY blue-ringed octopus that lives on the reefs around here. This is the Wikipedia information…..
The blue-ringed octopus is 12 to 20 cm (5 to 8 inches), but its venom is powerful enough to kill humans. There is no blue-ringed octopus antivenom available.
The octopus produces venom that contains tetrodotoxin, 5-hydroxytryptamine, hyaluronidase, tyramine, histamine, tryptamine, octopamine, taurine, acetylcholine, and dopamine. The major neurotoxin component of blue-ringed octopus venom was originally known as maculotoxin but was later found to be identical to tetrodotoxin, a neurotoxin which is also found in pufferfish and cone snails. Tetrodotoxin blocks sodium channels, causing motor paralysis and respiratory arrest. The blue-ringed octopus, despite its small size, carries enough venom to kill 26 adult humans within minutes. Furthermore, their bites are tiny and often painless, with many victims not realizing they have been envenomated until respiratory depression and paralysis start to set in.
The blue-ringed octopus, despite its small size, carries enough venom to kill 26 adult humans within minutes. Furthermore, their bites are tiny and often painless, with many victims not realizing they have been envenomated until respiratory depression and paralysis start to set in.
Absolutely lovely scenery and pictures. Those chicks are the equivalent of gold in weight, so delicate and so precious. I though that octupus was a butterfly! Nice post.
Fascinating post and I learnt quite a bit about oystercatcher ecology and behaviour. I was especially interested in the fact that the chicks swim and can even dive. I wonder if our Eurasian Oycs do that regularly. Here in Portland, Dorset they sometimes nest on a rocky breakwaters not connected to land. I wonder if the chicks are able to move from one to another on calm days.
As I said… fascinating. Thank you for posting.
love the chick in the footprint. just a great shot.
Also those who have not been lucky enough to see blue ring octo may not appreciate how difficult they are to find and how hard a shot that is to get. Tiny shapeshifting, camouflage changing inverts are hard to shoot at the best of times, harder still when they’re deadly.
Thanks for this wonderful post about “your” oystercatchers. I love the plover-in-footprint one as it really shows how delicate they are.
This is a surprisingly long-clawed predator, although this could be caused by it living on mostly soft soil / sand. Looks like a fox, but seems to be a bit small for one. I know cats can/do sometimes walk with claws extended on muddy or otherwise soft soil, so all in all your footprint has me baffled.
And yeah, Clare, that octopus … priceless!
There are no foxes in this bit of Australia-yet! I have been told that my problem cat in the northern section that we monitor is black-useful information!!! We have lots of footprints at nest sites and it’s depressing when you can see where the poor birds have tried hard to chase the cat away.
It is worth watching the Oystercatchers in the UK, as they are amazing swimmers here as chicks and even the adults here can dive in a real threat….you never know until you spend time with them!
Are you really sure this is a cat’s footprint?
Yes, got lots more photos. It is soft sand-can’t cycle in that area!
The reason I wondered is that I never found a track of a cat walking with extended claws that did not also show spread toes. This completely threw me. But then again, I have never tracked a cat on a beach… (and I am sure you wish you never had either!)
The wikipedia article on blue ring octopus annoys me. They were considered harmless until the 1950s, and there has only been 8 recorded bites ever, 4 of which were fatal. With only 8 recorded bites it’s hard to understand how it can be claimed that bites are “often” painless, or that “many” people don’t notice that they’ve been bitten. What percentage of those 8 didn’t notice, and even if it’s all 8 over the 0 years that we’ve known about them being poisonous, is that really “many?”
I don’t think you can take Wikipedia too seriously! We’d all be dead by now. It helps make Australia look like a deadly place to visit. I have never heard of anyone getting bitten here, though we do have about 4 people in a critical state in hospital each year from the irukandji jellyfish. If you look at the snake bite statistics for Broome area it is invariably someone in a drunken state that gets a bit silly and then gets bitten and dies.
I did some research on deadly animals in Australia earlier this year. It was hard to find good references, but this was the top 10.
1. Horse – 21 deaths/year.
2. Honey bee – 1.8 deaths/year.
3. All snakes – 1.6 deaths/year
4. Dogs – 1.5 deaths/year
5. All sharks – 1.0 deaths/year
6. All crocodiles – 0.7 deaths/year
7. All jellyfish – 0.6 deaths/year
8. Jack jumper ants – 0.4 deaths/year
9. European wasps – 0.4 deaths/year
10. All spiders – 0.1 deaths per year (but none since 1979)