H + T

Many years ago, prior to the great recession, I recall reading an article in a planning magazine that seemed to portend the coming great recession.  It talked about a number of persons who lived in Nevada, near Las Vegas, and would drive 3 hours one way to get to work near Los Angeles.  That is six hours on the road a day. Needless to say, they missed a bunch of their kids events, which made life in the way out suburbs more a drag than not. Some would leave early and catch a nap on the way to work and start the journey again.  And that is why H + T (Housing plus Transportation) is important. I don't think the article used the H+T acronym, so it probably came to the planning lingo after that article. H+T is a planning concept to consider commuting costs to work, as well as where one lives. When buying a home do not just consider the price of the dwelling, but also the cost for you to get to work and back.  Since most Americans drive their own car to commute, that means gas prices are important.

The people moved to Nevada because housing was much cheaper than it was in and near Los Angeles.  The problem is that when oil demand increased worldwide, and the economy improved, gas prices started to skyrocket. That means you spend more money on gas for the same distance traveled.  Just prior to and for the first several months of the recession gas prices peaked at $4.10 per gallon in July 2008. That seems like a good deal of money to the Millennial drivers of today who have become acclimated to gas prices in the two to three dollar range.  And even worse when you consider how low gas prices have become during Covid, being under $2.00 per gallon for many weeks in the past eight to nine months.

This graph shows US Crude Oil Production
from 1920 to 2017. Production significantly
increased  just after 2011, mainly due to fracking

Let me take an example for those long Nevada to California commuters.  If one commuted 150 miles to work one way, that is 300 miles a day. If you had a car that got 28 mpg for your commute that would work out to 10.8 gallons of fuel used per day, or 54 gallons per week.  If gas was $2.49/gal when you bought your home near Sin City, but then fuel prices increased to $3.89 there would be an increase of over $75 per week in fuel costs for the weekly commute.  If your commute was much less, say about 25 miles that increase could be more easily absorbed, but an extra $75/week starts to become substantial.  Showing how difficult this may make economic decisions, the drivers may have had to actually cut back on their latte or cappuccino purchases. Talk about sacrifice.

At that time, fracking, and shale were not as integral to keeping gas prices low.  Fracking and shale oil would arise in the 2010's to today.  Technology has allowed gas prices to moderate as production in the United States has increased.  Interestingly, low gas prices help drive economic growth.  US crude oil output increased at the same time of interest in green technology started to ramp up due to high energy costs of the prior decade. 

While showing the gap between new homes and resale prices
for the Las Vegas area, it also shows how home prices increased after 
2003 and then the drop with the recession from late 2007-2012

Housing is related to demographics.  The housing market was strong in the mid 1980's to early 1990's due to Baby Boomer purchases of houses.  My first interest rate when we bought was over 10%, an absurdly high number today.  Over the years, we refinanced down to just under 7%.  Generation X, those buyers of the homes in the Las Vegas area, were buying homes about 20 years ago, and hence there was demand and they bought far outside the area to increase their purchasing power for a larger home, or any home, at the expense of commuting. Today, housing costs are again high as the Millennial generation are now moving from their apartments to houses.  This of course, varies by market.  One can probably buy a lot or old house in Detroit for pennies of what it would be in a strong market area, like Madison, WI.  Of course, Madison's market is much more affordable for housing than that on the coasts.

Fitchburg has a good number of high end subdivisions, and in the 1990's to 2000's those were filled in part by professionals moving to Madison from the east or west coast, and here they could buy a much nicer house for $400,000 (back then of course) than they would ever be able to afford on the coasts.

Income generally rises as you age, but with a thirty year mortgage your housing costs remain stable.  This stability gives more certainty and the added benefit of more disposable income.  However, to make the initial cost house cost more affordable balloon mortgages were introduced.  Instead of a stable rate for thirty years the rate would increase at certain increments.  With a balloon you may not even have had an initial payment.  You simply push the cost down to a later point in time.  For short term thinkers, those raised on the sound-byte era, housing costs were, at least initially, reduced by the balloon mortgages which became common in the 1990's. Deal with the problem later.  With a balloon payment you lack certainty and that can eat into what you thought was disposable income.

Well, as the economy improved, the balloon payments were now taking effect, about the same time as fuel prices increased--in a few years leading to the great recession which started in the fall of 2007.  A perfect storm for some housing markets, and this would lead to a deep recession.  The housing crisis was precipitated in large part by the increase in mortgage costs as the rates started to increase, or balloon.  Add on top of your increased house payment, the cost for utilities and gas for your long commute, and you can see why a person should consider more than just housing costs when purchasing a house. These were the points of the article I read so many years ago.     

 

Doing Density

No this is not a blog post on about how dense I may be.  Rather it is about development density. My last blog post looked back to a paper I wrote forty years ago that focused on two rural subdivisions.  Back when I was growing up, it was often thought that large lots or acreages was best for a home, and for the environment. Many desire a house on large acreages, but is that the best way to live?  Several years ago as thinking "Green" became more important, a PBS production noted that Manhattan is the greenest place in the United States (and one of the greenest in the world), due to its density, and concomitant low carbon emissions.  Density does matter, but it does not have to be Manhattan density.  The New Urbanist movement likes density, but it also likes livable, human scaled neighborhoods.  Density can be effective at non-Manhattan levels. To New Urbanists, the maximum number of stories just outside a dense urban core is best set at a maximum of six stories for the next layer from the urban core.  (Although, in my mind three stories is a better human scale.) This allows a building to frame the street, but not so tall that it overshadows the human scale. Scale, whether height or density, is important.  This blog post will explain why doing density matters.   

1937 Air Photo of Fitchburg

When I was a planner I often recalled saying that if you develop at, say, four dwelling units per acre, you saved about twice as much land as if you developed at two units per acre.  Likewise, if you developed at six units/acre, you saved twice as much as if at three units per acre.  When working on what would be the 2009 Comprehensive Plan, we held over 100 public meetings, many of them workshops to obtain public input and get opinions. The idea of the workshop was to allow engagement, interaction and input by the public.  Perhaps the best workshop, in which the public came to appreciate our work, was the one held on the housing component.  This blog post will be on what we did at the workshop and how the public came to better understand the beneficial effects of density.  The workshop was slightly more complicated than what I will outlay here, but the meaning is generally the same. I may be fuzzy on some of the persons per household, but one gets the idea. Future posts will focus on my creation of Resource-Based planning, the created long-term growth boundary, experience with Transfer of Development Rights (TDR), and what planners call H+T.

1974 Fitchburg Land Use Plan Map

To understand density many 1970 to 1980 many suburban subdivisions were at a density of about 3 units per acre, net, or lots of an average of about 15,000 sq ft. Later subdivisions, were about 3 to 4 units per acre, and today, they could be even higher density, particularly some new-urbanist developments could be at 6 or 7 units per acre for single family. This is what we refer to as net density.  However, the public improvements (streets, storm basins, etc) is about 35% of the lot area.  Therefore, a 10,000 sq ft lot would have an actual development impact of about 13,500 sq ft. This creates gross density. (I recall testing that common 35% planning rule, and found it to be closer to 40% for many subdivisions, which I attributed to newer storm water regulations.)

The housing workshop drew a crowd of over 50 persons, which we broke into small groups.  The charge to each group was to plan the residential growth of Fitchburg. We provided a map of the city, and colored squares in ten or forty acre sections with a few density levels.  However, to make it more realistic they were required to meet the population parameters set for the city.  Working off of information from the State, Dane County Regional Planning Commission, and the UW Applied Population Laboratory, we know Dane County is a growing region of the state, and they allocated to Fitchburg a growth of about 5,000 persons a decade. Now, to meet 5,000 persons a decade, we provided them a few figures:  At an average density of 3 to 4 units per acre, or predominantly single family housing, there would be about 2.7 persons per household.  If they wished to consider a mix of residential densities, at say 6 to 8 persons per acre, the average person per household would be about 2.15 persons per household.  Given these figures, I, and a others in my office, went around to assist in calculations.  Each group would calculate and map out the number of households per acre, and add in the 35% development figure to reach gross density.  

2017 Air photo of Fitchburg

At the beginning most all persons in each group thought that it best to grow at single family density (most people who attend public meetings are single family homeowners and rural landowners showing a bias to single family). Simple math gives the area required:  5,000 persons divided by 2.7 persons per unit requires 1,852 dwelling units.  At 3 units per acre (net) that is 617 acres and add 35% gives 835 gross acres of residential development to be accommodated every ten years.  Seems fairly simple, and most thought the number was not too bad.  The problem came when they had to map this out.  Where would Fitchburg accommodate 835 acres of residential development every ten years, for three decades?  As the small groups discussed and mapped, they soon saw the rural area of Fitchburg disappearing before their eyes.  When taken over three decades, the then anticipated planning horizon, that meant they needed to allocate 2,505 acres of residential development (almost four square miles), or over 62 forty acre parcels.  As they saw the rural area disappear they then changed their calculations. (To provide a common reference point, the 160 acre land area common in the Homestead Act and for farms in the Mid-West is made of four forty acre sections.) 

Comprehensive Plan Workshop

As the public attendees went through their scenarios, most came to a conclusion of an average density of about 8 or 9 units per acre being a more sufficient density in order to preserve agricultural land. The Goldilocks principle. Some groups, who wished to preserve more land had higher densities. Due to a mix of dwelling units generally required to meet eight units per acre we reduce the density per household to 2.15 persons. (Multi-family units in Fitchburg have fewer persons per household, generally about 1.8.) This would require 2,326, dwelling units to accommodate a population of 5,000 persons a decade. However, at eight units per acre, the net area required would be 291 residential acres, or 323 acres of gross residential development for every ten year time frame.  That would be about 970 acres for thirty years, or just under 1.5 sq miles of land.  The number of 40's used would decrease to just about 24 forty acre parcels.This is a savings, over three decades, of 1,535 acres of land as compared to the three du/ac scenario.  Interestingly, about 7 to 8 units per acre is the level thought to make mass transit suitable for an area.

By allowing persons to see first hand how development can eat up land, they became more understanding of the need for a variety of housing options.  Fitchburg is rather unique as a city, since it urban, suburban and rural, and many of its residents view the rural area as important, in other words they are vested in the rural land, which may make them appreciate rural land more than in other cities where expansion into the rural areas is nothing big. As the persons per household continues to decline in part due to a decreasing marriage rate, fewer children being born, and boomers aging, varied housing options are necessary. Large lot single family no longer fits the population desires of some Americans.  Fitchburg has seen some significant growth in its new-urbanist subdivisions, and many residents who do not live in one of those houses complain about how close the lots are, but it fits a need, and can be more affordable than large lot housing.  I recall talking to persons who were calling about availability of neo-traditional housing options, and desire their own home, but also a desire for a small lot.  Less mowing and care.  At over $450 (2018 dollars) a linear foot, public improvements for an urban subdivision are expensive.  For a 50' wide lot the cost of improvements is $22,500, compared to an 80' wide lot at $36,000, on average.  

New Urbanist Development in Fitchburg

Since 1978 Fitchburg has not allowed for the creation of rural subdivisions (although rural cluster development was approved several years ago, but that is another story).  The question, could then arise, what if Fitchburg allowed only rural subdivisions?  A minimum one acre lot would be required to meet the necessary septic system requirements (primary and a replacement area), but let us assume an average lot size of 1.2 acres (52,272 sq ft) for 1,852 dwelling units, which would be 2,222 acres, or adding 30% (assume some on-site storm water) of the area for public improvements would take us to a required 2,889 acres for rural subdivisions to accommodate the 1,852 dwelling units.  This amount of acreage is equal to over 4.5 sq mi, or over 72 forty acre sections.  Just think what this would be like if all dwelling units in the county were on 1.2 acre lots! 

Density Allows for this (Heritage tree in Fitchburg)

Now, those are just development acres, but the actual impact is greater, since streams, wetlands and steep slopes cannot be developed, they often become corridors though a development, and hence would generally mean an increase in road, and utility length.  The greater area required, the more likely you are to have to work around the natural features. This is why density matters, and for those who live on large acreages should be quite happy that there are people living in Manhattan.  

The current politics of Fitchburg, from what I understand, tend to favor single family housing, and that market is currently strong.  The problem is that if Fitchburg only had a single family housing focus a decade ago, during the great recession, there would not have been much construction.  Because of its diversity, and its land use controls of the 2009 Comprehensive Plan, Fitchburg avoided the large swaths of single family home sites that tended to remain vacant for several years, with a city plowing a long stretch of vacant street, to get to one home; worse yet were the built but unoccupied homes that were mined for copper and other materials. Because Fitchburg allowed for multi-family construction, it saw growth in its tax base, unlike communities that only preferred single family where the tax base stayed generally steady or, in some cases, declined.  Before the recession, I received a call from HUD, asking about multifamily development in Fitchburg, and the person noted that there was a strong need in Dane County for that type of housing.  Prior to the recession, single family development was favored over multifamily leading to a high demand for multi-family housing. When I worked, I preached balanced and diversity of use in neighborhoods.  Having a variety of housing types allows a development, and a community, to better meet changing market conditions, and economic declines. That assisted Fitchburg through several tough years brought on by the great recession and the related single family housing crisis.

To show why, here is a thought to ponder:  The United States has an estimated 140 million housing units, with a total area of the fifty states (water included) being 2.43 billion acres.  That works out to one housing unit for each 17.35 acres in the United States. What do you think about that number?

Those who live on large acreages should be grateful for urban areas, and their residents. When you see homes that are near each other, think not of them as sitting so close, but how they preserve land. It is the urban area residents, who live at the higher densities, which allows for the open spaces and farmland we all enjoy. Density, studies show, leads to less carbon emissions.  That is one reason why Manhattan was considered to be the greenest place in the United States.  To preserve open spaces, to maintain or create livable communities, to balance varied values, is why as a Planner we held public workshops.  It is why planning matters.  Properly accomplished doing density benefits the nation, and in so doing benefits each of us.

Images from author presentation to Fitchburg Plan Commission, May 15, 2018.

A Land Use Look Back

Many years ago as a teenager, I recall looking out the window as my Dad would drive west out of Sun Prairie on Highway 19.  What struck me at the time were the rural subdivisions being created.  This got me thinking about the long term consequences of rural land use and how it affects farming, urban growth, and provision of public services.  My thought to have a career as a city planner began on car rides west of town.  Last week I came across a couple papers I did while in college.  As I perused these 40 year old papers, I realized how much work went into each product.  Devising a theory and then testing the theory.  This involved meeting and talking with different persons, surveys, data collection, literature review, and synthesis of the data and information to see how my theories held. Just the mapping, the old fashioned way was time consuming. Permit me to go back forty years to a different age. 

One of those papers, written in the spring of 1980, was titled "Motivating Forces in the Creation of Rural Subdivisions in Dane County, WI."  Running over 70 pages, the paper examined varied physical land factors, farming activity, land use, and development trends in Dane County.  What stands out is that the four main goals of the then 1973 Dane County Land Use Plan, were much as we see today in many land use plans.  Perhaps at some point I will do a test to compare those goals with how development now looks forty years later.  More specifically the paper examined two rural subdivisions in the county, one in the town of Bristol, north of Madison, and the other in the town of Oregon, south of Madison and Fitchburg.  Surveys of these subdivision residents were completed to understand the push and pull factors of choice of residence in a rural subdivision. I also talked with 21 different persons, today we would refer to them as stakeholders.  These persons ranged from the subdivision developers, to farmers who sold, nearby farm owners, to county and local officials. As I said in the beginning of the paper, the major emphasis was on the people involved, and to see how decisions, based on beliefs and perceptions, affected the transitional zone between city and country.  It is in these zones, as noted by Historian William Cronon, and which I know by experience, that conflict occurs. 

T of Oregon with Location of 
 Hillcrest Heights Subdivision highlighted

What was interesting was that of those that moved from a previous home to the rural subdivision expressed no strong push factor for relocating to a rural subdivision, yet, those from outside of the city of Madison spent little time looking for a home in what was their previous place of residence.  The main focus for those from outside of Madison was to examine rural homes. For example, 77% of residents in the Hillcrest Heights subdivision in the town of Oregon only looked for rural homes; the rate for rural home searches was lower for Sunburst in the town of Burke, which was 59%. Homeowners in Sunburst were younger and more were first time home buyers than in Hillcrest Heights.  The proportion of school age children was similar for both subdivisions.  

Sunburst Subdivision T of Burke

At that time, 75% of the residents of those two subdivisions were employed in the city of Madison, and 12% in a nearby small community. Interesting, given the time frame of 1980, over half the households reported both spouses being employed.  Of course, the exclusive method of transportation was by personal vehicle.  No ride sharing, and given the lack of density mass transportation would be highly inefficient.

The dynamic involved with these two towns is rather different.  Oregon, located further from Madison, and as noted separated from Madison by Fitchburg, is one of the few towns in Dane County to not have undertaken Farmland preservation and the related tax credits, and the next, and related step, of Exclusive Agricultural zoning (which does not mean much anymore). Both of these policies were being enacted throughout much of the county in 1978-1979.  In making conscious decision to not assist in preservation of farmland, the town of Oregon has seen a good amount of rural lot creation, by certified survey map, perhaps more so than by plat.  This led to an interesting dynamic.  Farmers who resisted the temptation to subdivide and create rural subdivisions in the later part of the 20th century, would see their land become "hostage," so to speak in their mind, to the rural residents who essentially desire to preserve the rural open space around their subdivision or dwelling. This fits the saying told by a former Fitchburg Plan Commission member: "that an environmentalist is a person who already has their house in the woods." The farmers who later wanted to develop saw it as rather hypocritical for new landowners how built on good farmland to now not allow the conversion of another farm.  Not in My Backyard (NIMBY) is not at all a recent trend.  If the farmer had subdivided earlier, before control of the town switched from farm land owners to non-farm rural landowners, there would have been a greater loss of farmland, but perhaps more equity in the decision process.  What the situation in the town of Oregon showed is the need for proper planning.  Instead they got ill feelings and divide, and its unplanned nature has led to some who felt disenfranchised.  Planning is important, as I found that often people will can grasp when planning is logical and based on natural resources, and service capabilities. A rural landowner or farmer may not have liked the plan, but they would have understood. Planning moves away from frivolous decision making.  

Detail of Hillcrest, outlined area was
subdivision in 1979-1980

What is interesting, is that farmers I interviewed for my 1980 paper were concerned about the very issue of non-farm residents gaining control and then controlling their farm decisions, demanding more public services, or prohibiting them from rural development.  At the same time the rural non-farm residents want the farmland preserved, they have no problem complaining about farm odors, farm traffic, or other aspects they view as undesirable.  On the other hand, farmers complain about these things, but when they want to develop these concerns go away.  As an employee under me once stated, the Agricultural and Rural Affairs Committee in Fitchburg was not farm friendly, but farmer friendly.  There is a difference. In the town of Oregon, those who continued to farm were, as it turns out, were right.  The non-farm landowners gained control and would prevent much new subdivision, but not necessarily large lot creation by certified survey.  Most of the non-farm residents live on land that was previously owned by a farmer, and subdivided, but subsequent land owners were not now allowed to do the same, due to change in town control..  Farmers, rightly or wrongly, view their land as their 401k (I cannot count the number of times I heard this statement), and subdivision makes more profit than selling for farm land, at least in Dane County. 

The farmers who controlled the town of Oregon lost control, and what they thought would be their rights, without farmland preservation and agricultural zoning, to realize a greater profit from their land holdings failed to materialize in some cases. Those disenfranchised farmers would have been better off supporting planning with farmland preservation and Exclusive Agricultural zoning as they would have at least received some tax credits for retaining farmland.  

T of Burke, Sunburst Subdivision Location Highlighted

The town of Burke, or the little that remains from annexations by Madison and Sun Prairie, will go away in 10 to 15 years as it is absorbed by those two communities through an intergovernmental agreement.  Burke has created more rural subdivisions, and of interest to Sunburst is, at the time it was beyond the extraterritorial reach of both Madison and Sun Prairie.  The 1973 Dane County Land Use Plan goal of creating distinct and separate communities is not realized in the case of Sun Prairie and Madison.  They, by choice, have decided that the perceived economic value of suburban office buildings in the American Center (what will the office market be like after Covid?), big box sprawl (Prairie Lakes in Sun Prairie) and large apartment buildings along USH 151 is more important than community separation and community identity.  Growing up, one of my classmates parents owned the land that now comprises part of Madison's American Center, a large suburban office project anchored by American Family Insurance. In my estimation, it was that project, more than any other, that started the land wars along Hwy 151 between Madison and Sun Prairie.

Detail of Sunburst Subdivision, 2017 air photo

What did my 1980 paper conclude?  First, the general consensus of planned growth falls short when disagreements over local autonomy arise.  This is really nothing new, and the Capital Area Regional Planning Commission was neutered, so to speak, by similar thoughts. In 2015 legislation was passed allowing towns to divorce themselves from Dane County zoning; Dane County was often thought to be the impediment to rural subdivision activity.  Second, specific to the subdivisions, both sites passed from dairy to cash crop when sold to a non-farm owner, and then to subdivisions. The shift to non-farm owners, at least at that point tended to occur by retirement or death of the main farmer. Third, my study also found disinvestment in agriculture, particularly in the town of Burke.  This disinvestment presaged the takeovers by the cities of Sun Prairie and Madison.  Given the lucrative location of the town along USH 151, 51, and 90/94, is it no wonder there was disinvestment to await greener pastures?  Fourth, there was a five or more year supply of rural lots, meaning holding costs for the subdivider, not to mention the towns having to plow and maintain roads little used. Fifth, Burke was attempting to balance agriculture, and other land uses, but I think that became met with futility given urban expansion of Sun Prairie and Madison.  Finally, the sprawled development leads to greater costs for the municipalities than otherwise thought or intended, not to mention energy costs (recall this was 1980) for commuting.  In rural development nothing is really convenient but your view of the corn field nearby.

Preservation of farmland becomes more difficult in uncertain economic times, and as more and more farmers struggle with low commodity prices and high expenses, the agricultural land that remains within a commute range of an urban core are more becoming horse havens, than farms.  I came to conclude that at least the land is preserved and hay is a decent crop, with little erosion potential, and the horse farms are much better than a rural subdivision.  Agricultural statutes do not recognize horses as an agricultural venture, as raising cows, chickens, or pigs. Some seem to think that there is more land out there to grow our food, but this part of Wisconsin has some of the best farmland and climate in the world, and we allow it to be swallowed like a small bird by a cat.

Development along Hwy 1951 is to left, and angle 
road at southwest corner is interstate.  The line between the S and P, for
Sun Prairie, is a strip of land in the t. of Burke

Rural subdivision activity is still occurring in parts of Dane County.  Traveling along County G to Donald Park, one can see the public improvements for a new rural subdivision which the realty sign says will consist of 1.5 to 2.2 acre lots.  This is the town of Verona. The town of Verona, like the town of Oregon, was never part of the Exclusive Agricultural Zoning and Farmland preservation. The issue of local control dominates in many aspects of land use planning. I may do further blog posts on this topic, but one thing I have noticed in my experience is that the we are losing a land ethic.  With over 32 years in local governments, I think this has been occurring for many years, and even prior to the great recession, although its decline was hastened by the great recession.  (The relation to the great recession to the decline of the land ethic is rather ironic, which perhaps is another blog post.) And now, many years later, as I travel on Hwy 19 Sun Prairie is now part of Token Creek and urban sprawl of Deforest/Windsor stretches south of Hwy 19 between 51 and the interstate. But, for the creek that runs across part of 19 and its related wetland, the corridor is basically developed, showing that there is no community separation. 

Images from Dane County Interactive Mapping System

Birds and Cats

The book I am currently reading, Upheaval: Turning Points for Nations in Crisis (2019) by Jared Diamond, had a statement that surprised me.  Talking about windmills for power production he noted that the windmills are estimated to kill an average of 45,000 birds and bats a year.  That seems like a lot of birds and bats. He then puts the number in perspective>  He notes that pet cats which are allowed to wander outdoors have been measured to kill an average of more than 300 birds per year per cat. You read that right, THREE HUNDRED a year.  

Feral Cats in Hawaii

Birds are important to our overall ecosystem, and, according to "National Geographic" (January 2018) our souls.  That is the why 2018 was the year of the bird in that magazine, noting the trails and tribulations they face.  Birds seem rather common, but many bird species have been killed off.  A "Smithsonian Magazine" article (dated Sept 20, 2016, and found online) references one scholarly paper which states that 33 extinctions of bird types are related to cats.  I think the study was mainly on islands, where birds are rather captive. Birds are important regardless if on an island, or mainland.  I suppose they may be more important for the small island ecosystem, not that birds are not important on the mainland.

Diamond goes on to say that the US cat population is estimated at 100 million, and hence that equates to 30 billion (yes, BILLION) birds lost to cats a year.   That Smithsonian article, which is a few years older than Diamond's book, says the number of cats in the US is 86 million, still a large number.  Cats, it says, are more popular as pets than dogs.  While all cats are blamed for the bird carnage, Smithsonian goes on to say that a quarter to a third of cats are outdoor cats, and they are the main murderers. The following story is relayed by the author of the Smithsonian article: Tibbles, a cat, traveled to New Zealand with her owner in 1894, and "there she single pawedly caused the extinction of the Stephen's Island wren. A small flightless bird found only in that part of the world." The article goes on to say that most pet cats, kill on average two animals per week (mammals and birds), quoting the Wildlife Society. The solution is to bring and keep cats indoors.  

Indigo Bunting

Cats get their own Broadway show, having humans dressed as that sneaky, snide animal, and floating around stage.  I only recall watching part, but urban stray and feral cats are involved, I think.  What do birds get?  they get the Birdman of Alcatraz, one of the most notorious criminals in the United States. Does this show where the nation's heart lies?  Robert Stroud, the Birdman of Alcatraz has a Wikipedia page, and there is a quote that says he was a '"first-rate ornithologist and author," but was an "extremely dangerous and menacing psychopath, disliked and distrusted by his jailers and fellow inmates."' The book and movie about Stroud shows him a much kinder light than many say he deserved.

Birdman of Alcatraz, R Stroud
US Govt photo from Wikipedia

The main issue is the non-owned stray and feral cats, however. Feral cats are basically wild animals and in some instances a human caretaker may feed them and watch over them, which Smithsonian says "subsidizes" them.  The subsidization allows the feral cat population to sore.  My step mother was a cat lover, but my dad was not, and she was one who subsidized feral cats seen around the large yard.  She was also a bird lover.  I always thought there was some incongruity in her two loves--cats and birds, but never explored it with her.  I recall going to the basement of the house and finding cat feces; I found out she let the cat in the basement during cold streaks. I think she may have had them neutered, probably to help protect the birds. Getting back to Diamond's number of 100 million, he may add in feral cats which are estimated to be 30 to 80 million in the US (if he adds in, he is obviously kind to the number). 

Feral cat advocates, and biologists agree that there are too many feral cats.  In high priority areas, the Smithsonian article quotes a specialist as saying, they must be trapped and never returned.  Trap and release elsewhere seems to move the problem somewhere else.  The Smithsonian article goes on to say that if they cannot be trapped other measures must be taken--be it select poison or hunters.  The trap, neuter, return method has been used in some cities, and which the feral cat advocates prefer.  However, many ecologists say the method is problematic as to be of some success it would require over 75% of cats in a colony to be sterilized and that does not happen.  Short term reductions in colony size, they say, is quickly reversed. One cat specialist Smithsonian interviewed says the TNR method is no solution at all.  He and others call for widespread removal and euthanasia. Of course, what would be the unintended consequences of ridding cities of the feral cats?  Would rodent populations, rats and mice in particular, get even larger than they exist today?

Baltimore Oriole
Taken through a screen, sorry about lack of clarity to photo

Australia hopes to kill two million cats per year using robots, lasers and poison. New Zealand has "mass warfare on possums, stoats and weasels in a bid to save its beloved birds." Like many things, the US cannot agree on an approach, with advocacy groups on both sides.  Who ever knew there was an Alley Cat Association?  Incremental carnage of birds can cause real problems.  It did not take people long to kill off the passenger pigeon, and cats can already lay claim to have caused the extinction of  33 types of birds, and I suppose that number will only grow.  Personally, I am not a cat person, but if you own a cat, keep it indoors.  Thirty billion birds a year, is a lot of birds.  Or, perhaps, get a dog.