The national population of Horned Grebe is monitored by both the Christmas Bird Count (CBC) and the Breeding Bird Survey (BBS). The CBC is less standardized than the BBS, but has potential to sample a broader cross-section of the Canadian population, and has higher precision in its trend. The long-term CBC trend is within the range of little change, with current abundance 21% above the early 1970s. Conversely, the national BBS trend over the same period shows a large decrease of 57%, with regional declines ranging from 36 to 39% in the northwest end of the breeding range to over 80% in southern British Columbia. Although the CBC is considered to be marginally more reliable than the BBS for Horned Grebe, the conflicting results limit overall confidence to low. 

For the Magdalen islands population, targeted surveys show that it declined at a rate of 2% per year between 1993 and 2007 (COSEWIC, 2009). Although annual nest counts have ceased, staging site surveys have been fairly regularly conducted since 2012 and show a further decline. In 2018, only 5 birds (adults and/or young) were observed, and since 2013, a maximum of 9 birds have been observed in any year (F. Shaffer, ECCC, unpublished data). Although it is possible that some birds may be using an un-surveyed staging area, the high public profile of this subspecies in the birding community and the small size of the Magdalen Islands suggests that this is unlikely. Because of this, there is high confidence that this population has undergone a large decrease since 1970. 

The national goal for Horned Grebe is to remain at or above its average population level from 1970 to 2022, based on the continental analysis of the Christmas Bird Count. Recent data show that the population is within its goal range. This is consistent with the Management Plan for the western population of Horned Grebe under the Species at Risk Act, which calls for maintaining populations from 2022 to 2052 at or above the average population from 1987 to 2017, while maintaining the current distribution of the species in Canada (ECCC, 2022).

The Recovery Strategy for the Magdalen Islands population under the Species at Risk Act is to maintain a minimum population of 30 individuals (Environment Canada, 2013). Recent monitoring data show that the Magdalen Islands population is below its goal range.