Dr. Lance Vrieze comments on EAW

Dr. Lance Vrieze’s additional comments on EAW:

Comment: The  EAW repeatedly  misuses  public data  in making  claims.

The EAW attempts to use public databases to support claims, but mischaracterizes the scope and methods for obtaining that data to present it in a disingenuous and slanted fashion. Rather than presenting a balanced scientific view, the EAW cherry-picks data to present. For example:

1) The Blueline-Xenops report makes a claim that:

The most comprehensive database on GBH rookeries in Minnesota comes from the 2014, when the MNDNR’s Minnesota Biological Survey (MBS) program conducted focused, state-wide surveys for GBH nesting locations in Minnesota, and published a Great Blue Heron breeding map for the entire state (Figure 6). During this survey effort, the MNDNR identified breeding GBH colonies in all but four Minnesota Counties. In Olmsted County the survey identified the 8th Street rookery in Section 5 of Rochester Township that is detailed in this report and also identified rookeries in Marion Township at Chester Woods and in Rock Dell and High Forest Townships. [All errors as found in the original]

 This is not at all what the data represent. The background methods and scope are all on the same website, a click or two away from the map (Figure 6) that they pull out to put in the report (https://www.dnr.state.mn.us/eco/mcbs/about_bird_maps.html). First of all, the MBS survey was not designed as a focused search for heron nesting locations, but rather a general survey of all birds. The featured map does not show the location of breeding colonies as stated in the EAW, but rather only shows that a bird was observed during the survey. Thus it is untrue that rookeries were identified in Marion, Rock Dell, and High Forest Townships; it simply means that a heron was seen! Further, stating that the survey identified the 8th St. Rookery in Section 5 (wait! Wasn’t it previously claimed that that rookery was in Section 6? Now I’m confused.) is in no way supported by the cited Figure 6. There is no red dot shown on the map anywhere near that part of the county. The EAW misinterprets and slants easily accessible public data in such a way that it calls to question the veracity of every statement in the report, many of which are not so easily able to be scrutinized.

 2) The Blueline-Xenops report also claims that:

While GBH breeding locations (“probable” and “confirmed” – blue dots in Figure 5) appear to be relatively sparse compared with observations of individual GBH (green dots in Figure 5), it is important to note that the MNBBA surveys consisted of 10 minute point counts to document presence of all bird species, and did not include any focused searches for nests or nesting colonies of GBH or any other species.

This statement is also false and easily refuted in the methods section of the Breeding Bird Atlas website (https://mnbirdatlas.org/data-and-methods/data-collection/). In fact, while there were some limited 10 minute point counts that contributed some data to the Breeding Bird Atlas, mostly to assist in statistical modeling, the vast majority of the data were collected by volunteers assigned to a specific area and tasked with doing EXACTLY what the EAW says was not done—focused searches for nests or nesting colonies of GBH or any other species. I know this because I was one of the volunteers that assisted in this and am acknowledged as such on the atlas website (https://mnbirdatlas.org/about-the-atlas/volunteers/). In addition, members of the Minnesota Ornithologists’ Union were encouraged to submit incidental reports of breeding behavior wherever and whenever they came across them. I also contributed much data to the atlas in this way. Thus, almost all of the data contributing to the map cited in the Blueline-Xenops report (Fig. 5) was not from rigorous point count surveys as stated in the EAW.

This misrepresentation or misunderstanding of the methods used to obtain the data in the Breeding Bird Atlas means that their conclusion about green dots in Figure 5 (Blueline-Xenops report) indicating the presence of a rookery in that township is far from true. The green dot only indicates that a great blue heron was seen in that township one time during the five year survey window and nothing more. The blue dots are a closer representation of the distribution of rookeries within the state.

It is also interesting that the EAW misconstrues data from the Breeding Bird Atlas to try and make a case for the “ubiquitousness” of heron rookeries around Minnesota yet ignores other salient points in the same publication. For example, the Breeding Bird Atlas states that, “In Minnesota, the heron is abundant enough to generate a robust population trend line; it has demonstrated a significant and steady decline, averaging 1.32% per year since 1967.” Also in the BBA it is stated that, “The biggest concerns for the future of the species are the protection of wetlands and the availability of secure nesting sites.” These examples show how the EAW is a one-sided presentation of misinterpreted, cherry-picked data rather than an unbiased report. 

Photo by William Welke