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The site was identified as internationally important for bird conservation in 2009 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
Black Stork Ciconia nigra	LC	non-breeding (1993–2009)	4–16 individuals	C6
Boreal Owl Aegolius funereus	LC	breeding (1995–1998)	1–2 breeding pairs	C6
Hen Harrier Circus cyaneus	LC	winter (1990–2005)	5–10 individuals	C6
Red Kite Milvus milvus	LC	breeding (1997–2009)	3–5 breeding pairs	C6

Ideally the conservation status of the IBA will have been checked regularly since the site was first identified in 2009. The most recent assessment (2009) is shown below.

State (condition of the key species' populations)
Species	Actual vs Reference (units)	% remaining	Result
Common Quail Coturnix coturnix	7 / 7 (males)	100	favourable
Black Stork Ciconia nigra	16 / 16 (individuals)	100	favourable
Circus cyaneus	6 / 6 (individuals)	100	favourable
Red Kite Milvus milvus	4 / 3 (breeding pairs)	100	favourable
Whinchat Saxicola rubetra	2 / 20 (-)	10	very unfavourable
Meadow Pipit Anthus pratensis	2 / 19 (-)	11	very unfavourable
Motacilla flava	2 / 15 (-)	14	very unfavourable

Pressure (threats to the key species and/or their habitats)
Threat	Timing	Scope	Severity	Result
Agricultural expansion and intensification	happen­ing now	most of popul­ation/area (50–90%)	slow deteri­oration (1–10% over 3 gener­ations)	high
Natural system modifications	happen­ing now	few individ­uals/small area (<10%)	rapid deteri­oration (>30% over 3 gener­ations)	low

Response (conservation actions taken for the key species and/or their habitats)
Designation	Planning	Action	Result
Whole area of site (>90%) covered by appropriate conservation designation	No manage­ment planning has taken place	Some limited conservation initiatives are in place	low

Year	Protected Area	Designation (management category)	% coverage of IBA
1965	Parc naturel de l'Our / Naturpark Our	Parc Naturel (II)	98
1981	Hachiville-Kouprich Wetland	Humid Zone (-)	<1
1981	Hachiville-Kouprich	Humid Zone Buffer Zone (-)	1
1981	Hachiville-Am Dall	Humid Zone (-)	6
1988	Wincrange - Ramescher	Protected Area (-)	21
1989	Troine-Hannerhaassel	Humid Zone (-)	2
1993	Ramescher (Wincrange)	Zones protégées d'intérêt national - Réserve naturelle (Ib)	2
2002	Vallée de la Tretterbaach et affluents de la frontière à Asselborn	Zones protégées d'intérêt communautaire - Zones Oiseaux ZPS (IV)	93
2004	Vallée de la Tretterbaach	Zones protégées d'intérêt communautaire - Zones Habitats ZSC (IV)	13
2004	Hoffelt - Kaleburn	Zones protégées d'intérêt communautaire - Zones Habitats ZSC (IV)	3
2004	Troine/Hoffelt - Sporbaach	Zones protégées d'intérêt communautaire - Zones Habitats ZSC (IV)	2
2017	Sporbaach	Protected Area (Ib)	3
2017	Kaleburn	Protected Area (Ib)	3

Habitat	% of IBA	Habitat detail
Grassland	64	Humid grasslands; Mesophile grasslands
Artificial/Terrestrial	26	Arable land; Forestry plantations; Other urban and industrial areas; Ruderal land
Forest	7	Alluvial and very wet forest; Broadleaved deciduous woodland; Mixed woodland
Shrubland	2	Heathland; Scrub
Wetlands (inland)	1	Rivers and streams; Standing freshwater

Land use	% of IBA
rangeland/pastureland	64
agriculture	18
forestry	14
hunting	major (>10)
tourism/recreation	minor (<10)
nature conservation and research	minor (<10)

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Recommended citation
BirdLife International (2025) Important Bird Area factsheet: Valley of the Trëtterbaach (Luxembourg). Downloaded from https://datazone.birdlife.org/site/factsheet/valley-of-the-trëtterbaach-iba-luxembourg on 18/01/2025.