It is known from the temperate zone (2,900-3,500 m) with vegetation comprising montane shrubs and Alnus and Eucalyptus trees (B. P. Walker in litt. 1995), where it is found in the understorey of alder woodland (G. Engblom in litt. 2005). It feeds on mistletoe parasitising alders and other trees, e.g. Tristerix longebrachteatum (T. Züchner in litt. 1999, Clements and Shany 2001), and in patches of flowering uñico Oreocallis grandiflora (Lambert and Angulo 2007). It has also recently been reported to feed and roost in introduced Eucalyptus trees, although the species's degree of tolerance of Eucalyptus plantations (especially as breeding habitat) is unknown (F. Angulo Pratolongo in litt. 2005, D. Geale in litt. 2005). However, the unconfirmed sighting in the Llanganuco area was in the Polylepis zone at 3,600-4,000 m. Juveniles and immatures have been taken in February, March and June.

Aglaeactis aliciae is only known with certainty from a tiny area in the upper Marañón drainage of La Libertad and Ancash, west Peru (F. Angulo Pratolongo in litt. 2012, 2020, Nuñez Cortez 2015). Though there were historical records from Succha and nearby Soquián in La Libertad, the only location that produced regular records in the period 1979-2005 was El Molino in La Libertad (J. Hornbuckle in litt. 1999, Hunnybun 1999, T. S. Schulenberg in litt. 1999, Lambert and Angulo 2007), where (at least until 2003) the species was described as "locally common" (D. Geale in litt. 2005, Lambert and Angulo 2007). However, in 2006 field surveys found the species to be widespread and locally common within its reported historical range on the east bank of the Marañón, and, indeed, elsewhere (e.g. on the west bank of the Marañón and in the upper Chusgon Valley). The distance between the most northerly and southerly points where the species was found was 35.5 km (Lambert and Angulo 2007). The species was recorded for the first time in northern Ancash, 40 km south of the La Libertad sites, in 2014 (Nuñez Cortez 2015), lending credence to a previous unconfirmed sighting from the Llanganuco area in Ancash, c. 100 km further south (Fjeldså and Kessler 1996). Within the Chusgón Valley, there is an additional area of 155 km² within which the species could potentially occur (Lambert and Angulo 2007).

Conservation Actions Underway
CITES Appendix II. In 2009-2010, CORBIDI carried out an awareness campaign, the first for this species and one of the few conservation actions directed to this hummingbird (F. Angulo Pratolongo in litt. 2012).

Conservation Actions Proposed
Survey the Chusgón Valley and more widely in the Pataz area to investigate the possibility of the existence of additional subpopulations. Determine the distribution of A. cupripennis to judge whether there are distributional gaps between the two hummingbirds where A. aliciae might occur (T. S. Schulenberg in litt. 1999). Research the species's ecological requirements (T. Züchner in litt. 1999), in particular assessing the suitability of Eucalyptus plantations as habitat (Lambert and Angulo 2007). Investigate the species's taxonomic relationship with A. cupripennis. Safeguard remaining habitat. Pressure local authorities to include species-specific material in school syllabuses and to initiate a second awareness campaign. Create a reserve for this species (F. Angulo Pratolongo in litt. 2012).