Unidentified eggs, Mt Climie (Upper Hutt)

[Nikki McArthur]

Hi all,

On the 13th of February I was up on the summit of Mt Climie (Upper Hutt) conducting bird counts for the regional council. The summit of Mt Climie is vegetated in subalpine shrubs, herbs and tussocks, and the lower slopes are covered in montane beech and kamahi forest.

At two separate spots near the Mt Climie summit I came across small, uniform white eggs sitting on the ground in the subalpine vegetation. Both eggs were perfectly intact, giving me the impression that they'd been 'dumped' by a gravid bird that didn't have anywhere else to lay them.

As a bit of a diversion, I spent my lunch break that day browsing NZ birds online on my phone, attempting to match up the colour and size of these eggs with potential suspects likely to be found up on Mt Clime, and I didn't manage to come up with a convincing answer.

Rather carelessly, I let the matter go and thought no more of it until today, when browsing the very popular "Wellington City Biodiversity" thread on this forum, I came across the following post by Christopher Stephens from May 2023, with a photo of an identical egg he found in exactly the same spot:

viewtopic.php?p=54394#p54394

In his post, Christopher mentioned that his egg may have been that of a kākā, and a couple of other people suggested chicken or pheasant, but the identity of this egg seemed to go unresolved at the time.

Christopher didn't provide any measurements for his egg, but I did measure the two that I came across in February, dimensions were as follows:

Egg 1: 33.0 mm x 26.5 mm
Egg 2 32.0 mm x 26.5 mm

And here's a photo of my eggs (the scale bar on left hand side of the image is in cm - click on the photo to enlarge):

What on earth are they?? They're certainly too small for kākā, chicken or pheasant, and at any rate all three species are pretty unlikely to occur on the summit of Mt Climie. I initially wondered whether they were long-tailed cuckoo eggs dumped by a bird that hadn't managed to find a host nest, but they're too large and the wrong colour for LTC. The upper slopes of Mt Climie aren't exactly teeming with birds, so the list of likely suspects among the resident birds is pretty darn small - I went through them all on the day I found the eggs and couldn't find a match. These eggs are too large for any of the passerines, parakeets or eastern rosella (though the egg shape is a good match for the latter) and too small for kererū, rock pigeon or morepork. Thinking outside the box I even started checking seabirds. The measurements seem to be a close match for white-faced storm petrel, but the egg shape doesn't look right to me.

Any thoughts?

Cheers,
Nikki

PS: As an aside I found it rather laborious to trawl through a couple of dozen HANZAB extracts searching likely species for a match to these eggs, and it occurred to me that a matrix table of mean egg lengths vs mean widths for NZ spp would be a really useful resource for identifying mystery eggs such as these. Does anyone know whether such a table exists?

[bombaydave2]

Kea?

[Jake]

They're not too far off Sacred Kingfisher eggs for size. Plus the correct shape and colour.

They also sound like the exact size and shape for Domestic Coturnix Quail eggs... if they're hard-boiled, that's almost certainly part of someone's lunch. Some Coturnix Quail do lay uncolored eggs. These eggs seem not pointy enough for Bobwhite (or California) Quail. This is mostly thinking out of the box too, as you've already excluded so many species!

DNA sequencing might be your next step lol

[Jake]

New Zealand Birds Online has the mean size of Sacred Kingfishers listed as 29mm × 24mm; again not too too far off your 33mm × 26.5mm

[Nikki McArthur]

The identity of these mystery eggs may now have been solved, though the answer is a bit left-field. Ryan Bauckham has pointed out that the eggs are a perfect match for bobwhite quail (you were very close, Jake!). Ryan also points out that bobwhite quail hens frequently engage in "egg dumping" when they don't have access to a nest to lay in, which accounts for where Christopher and I found these eggs.

Very strange though...the birds themselves haven't been seen on Mt Climie as far as I know, and it's a bit of a mystery how they've gotten up there. Presumably released by an enthusiastic local aviculturalist, but the suspect list is likely to be quite small, as whoever it is will have needed a key to the locked forestry gate at the bottom of the hill.

The question that remains is whether there are still any surviving birds up there - Christopher found his egg in May 2023 and I found my two in February 2025, so there's either been one release and the birds have survived for some time, or there may have been multiple releases over this period.

Cheers,
Nikki

[andrewcrossland]

They look like feral rock pigeon eggs also - a species that nests on the ground sometimes. Are there any at this location??

[Nikki McArthur]

Hi Andrew,

No, no rock pigeons up there. We did speculate about the possibility of homing/racing pigeons dropping in, but this seemed a little far-fetched. Finding three of these eggs in three different locations over two years also suggests to us that they're being laid by a resident, rather than transient species.

Nikki

[Nikki McArthur]

...These eggs (33 x 26 mm) are also a bit small for rock pigeon (39 x 29 mm), albeit the right colour and shape.

[Jake]

I used to kept Northern Bobwhites, and my girls layed noticeably pointy eggs (Pyraform?); but then again, there's fair variation with gamebird eggs. If you *are* going with American quail, then I wouldn't rule out them having been bleached, and bleached California Quail eggs might be a higher likelihood than an escapee Bobwhite

[Neil Fitzgerald]

Nikki, did you measure your eggs directly with calipers, or from the scale in the photo?