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The site was identified as internationally important for bird conservation in 2014 because it was regularly supporting significant populations of the species listed below, meeting IBA criteria.

Populations meeting IBA criteria ('key species') at the site:

Species	Red List	Season (year/s of estimate)	Size	IBA criteria
Australasian Bittern Botaurus poiciloptilus	VU	resident (-)	present	A1
Black Stilt Himantopus novaezelandiae	CR	resident (1979–1992)	6–17 individuals	A1, A4i
Wrybill Anarhynchus frontalis	VU	breeding (1979–1992)	41–138 breeding pairs	A1, A4i
Black-billed Gull Larus bulleri	NT	breeding (1970–1995)	26–81 breeding pairs	A1
Black-fronted Tern Chlidonias albostriatus	EN	breeding (1979–1993)	70–224 breeding pairs	A1, A4i

Ideally the conservation status of the IBA will have been checked regularly since the site was first identified in 2014. The most recent assessment (2014) is shown below.

Pressure (threats to the key species and/or their habitats)
Threat	Timing	Scope	Severity	Result
Invasive and other problematic species and genes	happen­ing now	some of popul­ation/area (10–49%)	moderate deteri­oration (10–30% in 3 gener­ations)	high
Human intrusions and disturbance	happen­ing now	some of popul­ation/area (10–49%)	slow deteri­oration (1–10% over 3 gener­ations)	medium
Natural system modifications	happen­ing now	some of popul­ation/area (10–49%)	slow deteri­oration (1–10% over 3 gener­ations)	medium
Climate change and severe weather	likely in short term (within 4 years)	some of popul­ation/area (10–49%)	moderate deteri­oration (10–30% in 3 gener­ations)	medium

Response (conservation actions taken for the key species and/or their habitats)
Designation	Planning	Action	Result
Not assessed	Not assessed	Not assessed	not assessed

Year	Protected Area	Designation (management category)	% coverage of IBA
1953	Aoraki Mount Cook National Park	National Park (II)	8
1957	Lake Alexandrina Wildlife Refuge	Wildlife Refuge (IV)	7
1986	Lake Alexandrina	Scenic Reserve (III)	<1
1987	Lake Alexandrina	Stewardship Area (III)	2
1987	Sibbalds Island	Stewardship Area (III)	<1
1987	Godley Riverbed	Stewardship Area (III)	1
1988	Cass River Delta	Stewardship Area (III)	<1
1988	Micks Lagoon	Stewardship Area (III)	<1
1990	Te Wahipounamu – South West New Zealand	World Heritage Site (natural or mixed) (UA)	3
1999	Godley Macaulay	Stewardship Area (III)	<1
1999	Lake Alexandrina	Scenic Reserve (III)	2
2016	The Island	Stewardship Area (III)	4

Habitat	% of IBA	Habitat detail
Grassland	major (>10)
Introduced vegetation	major (>10)
Shrubland	major (>10)
Wetlands (inland)	major (>10)

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Recommended citation
BirdLife International (2025) Important Bird Area factsheet: Godley Cass Rivers (New Zealand). Downloaded from https://datazone.birdlife.org/site/factsheet/godley-cass-rivers-iba-new-zealand on 18/01/2025.