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Stancomb

Penguin breeding site · Coats Land · CCAMLR 48.5

Stancomb is a known penguin breeding site in the Coats Land, at 74°07'S 23°05'W. Emperor penguins have been recorded here. Emperors breed on sea ice rather than land, which makes this one of the sites whose very surface disappears in a bad ice year. The sea around it has gained ice at 3.51 points a decade since 1979 — 4.6 times its own standard error. The sea around it now clears about 19 Jan against 27 Oct at the start of the record — 84 days later.

RegionCoats Land
CCAMLR subarea48.5
Species recorded1
Sea ice Apr–Nov+3.51 %/decade
Mean ice within 100 km80%
Mean retreat date10 Dec
Retreat trend+19.1 days/decade
Site codeSTCB
Position74°07'S 23°05'W
Decimal-74.1203, -23.0867
Distance to pole1,766 km
Populationnot published — see below

Species recorded here

Emperor penguinAptenodytes forsteri

The sea ice around this colony, 1979–2024

0255075100197919902000201020202024 Apr–Nov, the platform months Nov–Dec, the fledging window+3.51 POINTS PER DECADE% SEA-ICE CONCENTRATION WITHIN 100 KM
Solid: April–November, the months a colony needs a platform. Dashed: November–December, when an early break-out takes chicks that cannot yet swim. The rule is the fitted trend through the April–November series. Fixed 0–100% axis.

Averaged over 34 ocean cells within 100 km, the April–November sea-ice concentration here has moved +3.51 ± 1.53 points per decade — fitted 72% in 1979 to 88% in 2024. That is a real gain: the slope is more than twice its own standard error above zero. Most emperor colonies are in this group, which is not the story usually told about them. Over the fledging window it reads +7.18 ± 2.65.

Two limits, and both matter. First, this is not the fast ice the birds breed on. At 25 km the land-attached ice emperors breed on is narrower than one cell and cannot be resolved. This is the sea around the colony, not the platform under it. Second, the archive ends 2024-12-31 — it is a climate record, not a current reading, and the live sea-ice figure on the wire is a different product entirely.

See all 67 emperor colonies mapped this way →

Is this an independent measurement?

1 other known breeding site lies within 200 km of this one, and the cells this measurement averages over reach 100 km — so this record and theirs are not independent readings of the sea. Thinned so that no two overlap, the 728 measurable sites in this archive become 56 places.

In the 2023 ice year — the last one this archive holds — the sea ice here lasted 353 days, which is this site's 27th shortest season of 41 and above its own median of 327. It was below the median at 657 of the 728 sites measured here and at 44 of the 56 independent places, which is the most widespread short season in the record: the whole archive is drawn in one frame.

And when that ice goes, 1979–2023

SEPOCTNOVDECJANFEB15 DEC · CHICKS CANNOT YET SWIM19791990200020102023 the day the ice fell below this colony's own normal before 15 Dec+19.1 DAYS PER DECADERETREAT DATE, ICE YEARS 1979–2023
One dot per ice year: the day sea-ice concentration within 100 km fell below this colony's own whole-record normal and stayed there. The rule is the fitted trend; the dashed line is 15 December. Fixed 1 September–6 February axis.

Across 36 usable ice years the retreat date here has moved +19.1 ± 6.9 days per decade — fitted 27 Oct at the start of the record to 19 Jan at the end, a shift later of 84 days. The slope clears twice its own standard error, so that is a shift this record can claim — and it runs the other way from the colonies losing their platform early. Since 2000 the sea here has opened before 15 December — the point in the breeding calendar at which a chick still cannot swim — in 9 of 20 ice years. On the stricter 15% threshold — the day the sea around it opens outright rather than falling below its own normal — 13 of the 36 ice years never clear at all, so the figure above is the one to quote.

Two uncertainties, not one. The fit above carries ±6.9 days per decade of its own. The archive carries a second one that no other site prints: before 1988 the satellite flew every other day and the producer filled the missing ones, so 8 of 3,287 daily readings at this colony in that era — 0% — were interpolated rather than observed, and nothing in the data says which. Propagated through this particular fit, that is worth ±0.1 days per decade — a fraction of the fit's own. Both are printed; neither is folded into the other.

This is the day the sea around the colony opened, not the day the fast ice under the birds broke out — a 25 km cell cannot see one bay. An early exit here is a plausible companion to a bad season and never a cause of one. See all 61 colonies dated this way →

And how long that ice lasts, 1979–2023

15 FEBAPRMAYJUNJULAUGSEPOCTNOVDECJANFEBWHEN IT GOES +19.1 D/DECWHEN IT ARRIVES -21.1 D/DEC · NOT ROBUST19791990200020102023SEA ICE PRESENT AROUND THE COLONY, BY ICE YEARone bar per ice year — sea froze to sea opened+40.1 DAYS OF SEASON PER DECADE
Each bar is one ice year: the sea within 100 km of this colony sat above its own whole-record normal from the bottom of the bar to the top. The dashed rules are the two fitted ends — solid colour where that end clears the gate, grey where it does not. Fixed 15 February–14 February axis.

Across 36 usable ice years the sea-ice season here averages 256 days and has moved +40.1 ± 13.6 days per decade — fitted 163 days at the start of the record to 340 at the end. That clears both gates — twice its own standard error, and still that with the pre-1988 sensor dropped. It runs the other way from the colonies losing their platform. The change is at the break-up end: the ice goes 19.1 days per decade later, while the freeze-up date does not clear its own error bars. In 5 of 41 ice years the sea here was still above its own normal when the ice year opened, so the freeze-up date is censored at the start of the year rather than measured.

The two ends add to that figure exactly, because within one ice year the season length is the retreat date minus the freeze-up date: +19.1 days per decade from the ice going, +21.1 from the ice arriving. See all 61 colonies measured this way →

And a second uncertainty, of a different kind. Before 1988 the satellite flew every other day and the producer filled the missing ones: 8 of 3,287 daily readings at this colony in that era — 0% — were interpolated rather than observed, and nothing in the pixels says which. Measured against a ground truth and propagated through this particular fit, that is worth ±0.5 days per decade against the fit's own ±13.6. The two ends carry their own: ±0.1 days per decade on the ice going and ±0.4 on the ice arriving. Those three figures are not added together — the trend decomposes exactly, but the uncertainties behind it were each measured over a different set of ice years, so each belongs to its own slope.

Why there is no count on this page

Penguins are too small to resolve from orbit. What is visible is the guano stain a colony leaves on the ice, which is why counting from satellite is a colour problem rather than a counting problem — and it is not solved. Our own detector correlates at r = −0.16 against ground counts across eight colonies, which is no relationship at all. Until that is fixed, this site publishes locations and says nothing about numbers. A number we cannot defend would be worse than none.

Nearest breeding sites

Nearest stations

60°SSTANCOMB
Stancomb in Antarctic Polar Stereographic. Rings are 60°, 70° and 80°S.
DrescherHalleyDawson-LambtonRiiser-LarsenLuitpoldHalley VIWasaN212 KM
Within 424 km. Blue dots are other breeding sites, orange are stations.