Minnesota's extensive library of books about its birds received a substantial addition recently when the University of Minnesota Press published "Birds in Minnesota."

This is yet again a revised and expanded edition of a book that had its beginning as a vision in author Robert Janssen's mind when he was barely out of grade school.

He is now in his 80s, enthusiasm undimmed, although he does move a bit more slowly.

Minnesota's birds are illustrated, of course, in the many guides to identification of North America's avifauna. Those books put a name to an image.

Janssen's efforts seek to "tell readers what species have been reported in Minnesota, in what parts of the state they are found, in what seasons they are present, and how abundant they are," to quote from the author's preface.

In 1945, at age 12, Janssen spent the mighty sum of $15 for the two-volume set of "The Birds of Minnesota," a 1932 publication written by Thomas Sadler Roberts, who began his records of our birds in 1879.

Janssen started his first year list — bird species seen in a calendar year — two years after he carried those books home.

His lists and Minnesota birds became an obsession, he has told me, an accurate description, as friends and his wife will agree.

The new book is 583 pages, particularly useful thanks to the computer skills of Janssen's friend Dave Cahlander, and the extraordinary organizational and design skills of staff at the University of Minnesota Press.

The book is valuable now for its summary of the status of our bird life. It will be valuable 20 or 40 years from now as the tool that measures the changes certain to come.

Janssen did not do this on his own. The first iteration of the book appeared in 1975 with publication of "Minnesota Birds: Where, When, and How Many." That was a joint effort with Duluth birder Jan Green. Roberts' list of 320 species covered had grown to 374 by that time.

In 1986, with the state species list at 400, Janssen put revised information into a book also titled "Birds in Minnesota." Today, at 443 species, with many changes in distribution and seasonal dates, we are once again up to date.

Throughout, Minnesota's large base of active birders made thousands of contributions. Many keep detailed records of what, where and when. High on that list is Duluth birding guide and author Kim Eckert.

In the new book Eckert writes as its introduction an essay on "unique geography, diverse habitats, and rich avifauna" of our state. He clearly explains why our birding opportunities are indeed unique, diverse and rich. He gives us an education in Minnesota birding.

Our state bird club, the Minnesota Ornithologists' Union, has for decades collected from members data on what, where and when. Others have spent recent years in special efforts to record the breeding activities of our birds, again what, where and when. Janssen had access to all that data.

He had help over the years from many friends and colleagues. In particular, he mentions the late Ray Glassel who, Janssen writes, introduced him to "the joys and tribulations of county listing."

As you may surmise, those are records of birds within county boundaries. Janssen has seen at least 225 species in each of our 87 such jurisdictions. By his estimate, he has driven nearly 3 million miles to do that, many with Glassel as co-pilot.

All of those miles, of course, are in Minnesota. Janssen proudly calls himself provincial when it comes to birds.

As this book demonstrates, everyone interested in birds here has benefited from that.

("Birds in Minnesota," University of Minnesota Press, 583 pages, 315 color plates, index, with thousands of maps and graphs as good as any you ever will see, $34.95, paperback.)

For other entries into Minnesota's copious library of birding books, search for "Minnesota bird books" online or on Amazon. There are dozens.

Lifelong birder Jim Williams can be reached at woodduck38@gmail.com. Join his conversation about birds at startribune.com/wingnut.