Sample text for Butterflies of North America / Jim P. Brock and Kenn Kaufman ; with the collaboration of Rick and Nora Bowers and Lynn Hassler Kaufman.
Bibliographic record and links to related information available from the Library of Congress catalog
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A Note from Kenn Kaufman
Most people seem to be aware of butter?ies more as symbols than as real
living creatures. Although there are hundreds of species of butterflies in
North America, they somehow escape public notice most of the time. Out in
plain sight, they lead secret lives.
I still recall how surprised I was when I began to notice them
myself. At the age of fourteen, having learned a lot of my local birds, I
decided to see if there were any butterflies in the neighborhood. Amazingly,
as soon as I began looking for them, they appeared: Little Wood-Satyrs
flopping through the woods, tiny Reakirt"s Blues on weed flowers in vacant
lots, and dozens more. Although I had been outside looking for birds, up to
that time I had utterly missed these other winged creatures.
Butterflies are not birds, of course. They are very different in their
habits, yearly cycles, and population dynamics. And they"re a lot smaller.
The biggest ones, like Monarchs and Giant Swallowtails, may grab our
attention, but most of the diversity is among the smaller butterflies. We
have far more species of little hairstreaks, blues, skippers, and the like than
we do of the big guys. Small can be beautiful: even the tiniest butterflies have
intricate patterns that are well worth appreciating. But until recently, it has
been extremely difficult to identify many of these butterflies in the field.
Even separating some larger species has been problematic, because their
identification often depends on small details. Until the recent development
of good close-focusing binoculars and cameras, many butterflies could be
recognized only by expert lepidopterists with vast experience.
I have been lucky enough to have one such lepidopterist as a
good friend for years, and luckier still that he is the kind of expert who is
always ready to share his knowledge. Jim Brock has studied butterflies
from Alaska to Brazil, and in the field he dazzles everyone with his ability to
find and identify even the rare and little-known species; but he will also
patiently point out the most common butterflies to anyone who wants to
know them. Jim agreed to coauthor this book as a way of helping new-
comers to the field. In doing so, he graciously accepted the challenge of our
Focus Guide format: boiling his vast knowledge down to just the essentials
that would be most useful in a pocket-sized book. If any serious
lepidopterists are displeased by the treatments here, they should blame me,
not Jim Brock.
But of course serious lepidopterists (who already have their
technical reference works) are not the primary audience for this book. The
Focus Guides are shortcuts, intended to be the best and fastest way to get
started in a subject, to send you outside quickly, putting names on what
you find. Slip this book into your pocket the next time you go exploring, and
start discovering the secret world of butterflies for yourself.
In naming a butterfly, the first step is to make sure that it really is one. The
order Lepidoptera includes the moths as well as the butterflies, and some
moths are active by day and are quite colorful. Usually they sit or behave in
an obviously different way from butterflies. If in doubt, look at the antennae.
On butterflies, the tip of each antenna has a thickened area, or "club." North
American moths lack this feature; their antennae are either threadlike to the
tip, feathery, or fringed along the edges.
Butterflies have four wings: two on each side, the forewing and the
hindwing. The upperside and underside of each wing usually has a different
pattern. To describe a color pattern on a butterfly, therefore, we have to say
where it is — for example, on the upperside of the forewing. Lepidopterists
can describe butterfly patterns in great detail using a system of numbering
the wing veins and the spaces between them. It"s hard to apply that system
to an active butterfly in the wild, so we don"t use it in this guide, except to
point out the cell, an area outlined by veins near the base of each wing.
However, a few terms are necessary for communicating about the intricate
patterns of some species; see the diagrams below for the simplified
terminology used in this guide.
What to look for: Wing patterns are obviously important in identifying
butterflies, but they are not the only clues. Here are some other points to
Size: Some swallowtails are six inches or more from one wingtip to the
other, while some blues are much less than an inch across. Since these
wingspan measurements are hard for most people to visualize, we have
treated sizes in this guide by showing one individual on each color plate at
actual life size in gray outline. The illustrations are in correct scale relative
to the others on that page, but not necessarily to those on other pages; be
sure to check the "actual size" figure each time you turn the page, to get an
idea whether the butterflies shown are actually big, medium-sized, or small.
Little butterflies do not grow up to be big ones: once they
complete the transformation to winged adult, their size does not change.
However, there are variations within a species. Early spring individuals are
often smaller than those of summer; females are often larger than males.
And occasionally we see a "runt" individual that is oddly small. But with
experience, you will find that size is usually a good quick clue to
Shape: At a glance, most butterflies may seem to be roughly the same
shape. With closer study, you will begin to see differences in wing shapes
that help to create the distinctive look of each species. Some have
extended "tails" on the hindwings, or jagged or scalloped outer wing
margins. Other differences are much more subtle, such as the wingtips being
slightly more rounded or pointed. But with practice you will find that a
butterfly"s shape is an important identifying mark.
Posture: The way a butterfly sits is always worth noticing. Sulphurs almost
always perch with their wings folded tightly above their backs; metalmarks
usually have their wings spread out flat; cloudywings usually hold their
wings half open in a shallow V; and grass skippers often hold their hindwings
spread farther than their forewings. Any butterfly may sit in an odd position
at times, but the typical posture can be a good clue to identification. We
have tried to illustrate and describe this for all species.
Flight style: Experts often can recognize a butterfly as it flits past — not
because they can actually see detailed field marks on its fast-moving
wings, but because the way it flies is a field mark in itself. Some species fly
erratically, others more directly; some flutter along with regular steady
flaps, while others flap a few times quickly and then glide. These flight styles
are hard to describe in words, but with practice you will learn to recognize
many of them.
Fine details: Some field marks involve very small details, such as the colors
of the eyes, the color or pattern on the antennae, or the color of the "face"
(the palps, on the front of the head). These things really can be seen in the
field, but for wary species you may need to use binoculars. Good
binoculars are now available that can focus as close as just a few feet away,
allowing incredible views of butterflies and other small creatures. One good
source of information on binoculars for butterfly-watching can be found online
Variation in butterflies: As with humans and other living things, no two
individual butterflies look exactly alike. Most of the variation within a
species is so minor that you won"t notice it in the field, but sometimes it"s
enough to cause confusion. Occasionally you"ll see an individual that looks
totally unlike the normal color pattern for its species; these aberrant
butterflies may be identifiable only by shape or other clues.
Many species vary from place to place, and if these variations are
well marked, a local or regional population may be designated as a
subspecies; see p. 14 for more information. There are also seasonal
variations. For example, Zebra Swallowtails flying in spring are smaller and
paler than those flying in summer, even though they all belong to the same
species; Goatweed Leafwings flying in fall have more sharply pointed
forewings than those flying in early summer. Males and females often differ
in pattern or even in shape — sometimes subtly, sometimes so strikingly
that they appear to be unrelated. And finally, every individual butterfly
gradually changes in appearance as its condition becomes more worn and
faded. The two Painted Ladies shown here, for example, were sitting on
flowers in the same meadow. The ragged one on the right can still be
identified, because Painted Ladies have lots of field marks, but some
butterflies in this condition would be unrecognizeable.
Habitat and season: Many butterflies are restricted to particular habitats,
and this is a key not only to finding them but to identifying them. We give
habitat descriptions for most species in this guide, and these should always
be considered. Seasons are important as well. Even in warm climates, only a
few species are on the wing year-round; in most species, adults are present
only in certain seasons. We usually describe these flight seasons in
general terms, such as "early summer," and these designations relate to
local conditions, not arbitrary calendar dates. The Sara Orangetip, for
example, is an early spring butterfly. It may appear by late January in
Arizona and not until the end of May in the Yukon Territory, but those dates
qualify as "early spring" in both locations.
About the illustrations: Naturalists have debated for years whether field
guides should be illustrated with paintings or photographs. This book uses
a third method, introduced in 2000 with the first Kaufman Focus Guide, Birds
of North America: we begin with photos and edit them digitally to make them
all directly comparable, as paintings would be.
Some butterflies, such as sulphurs, never bask with their wings
open; but it is still useful to know the colors of their uppersides, because
even at a glimpse in flight, a pale yellow one will look different from an
orange one with black borders. For most species like this, we provide
illustrations at reduced size showing their uppersides as an aid to
identification. Understanding the range maps: One of the most important
clues to identification involves knowing where you are. Most butterflies have
very specific ranges and are unlikely to be seen anywhere else. This is a
good thing, because some groups include similar species that are much
easier to tell apart by range than by field marks. For example, Eastern and
Western Tailed-Blues look very much alike, but in most places you will find
only one or the other, not both. In identifying any butterfly, always check the
range maps to see which ones are likely in your region.
Most of the range maps in this guide have the distributions of the
butterflies indicated in green. This color means that the species is flying in
summer (the peak butterfly season in most areas) or in more than one
season (for example, spring and summer, or even most of the year). We
use a darker shade of green for areas where the species is most common,
and a paler shade for areas where it is less likely to be seen. These
designations are quite arbitrary, but we hope they will be helpful in giving a
general idea of which species are most expected.
A few species fly mainly in spring or mainly in fall; these are
mapped in blue for spring, orange for fall, again with a darker shade for the
areas where they are more common.
Some butterflies, especially from southern regions, sometimes
stray far from their normal haunts. If there is a regular pattern of such
straying, we indicate it on the map with a dashed line beyond the typical
Some butterflies are adaptable and may show up almost anywhere, but
most prefer a particular habitat. You will not see Salt Marsh Skippers in a
forest or Desert Elfins in a marsh. To see a wide variety of butterflies,
therefore, it"s necessary to visit many habitats. You should go at various
seasons, because many species have rather short flight periods: Falcate
Orangetips fly only in spring, Apache Skippers only in fall. This adds to the
enjoyment of butterfly watching, because you can hope to see different
species on repeat visits to the same place during the year.
Flowers: Not all butterflies fit the classic image of visiting flowers to sip
nectar — some species are rarely or never seen at flowers. Still, to get
started, the easiest way to find butterflies is to find a good patch of blooms
in a garden or meadow, or by a roadside. Some flowers seem to be more
attractive than others, and some butterflies prefer certain types of flowers,
so it pays to look in a variety of places.
Mud: Males of some butterflies, including blues, swallowtails, and sulphurs,
are strongly attracted to damp soil. They are apparently taking in salts and
other chemicals from the mud. Sometimes these "puddle parties" involve
several species and hundreds of individuals, while at other times only a few
individuals will be present, but you should always check puddles and pond
edges for the presence of butterflies.
Other baits: Many butterflies are attracted to odd things such as flowing
sap, rotting fruit, or animal dung. (This is especially true of some species that
tend to ignore flowers, such as the Goatweed Leafwing and the Question
Aside from these feeding behaviors, adult butterflies put most of their
energy into activities related to reproduction. Males spend a lot of time
looking for females; females spend much time looking for the right places to
lay their eggs. Knowing their behaviors can help you find them.
Hilltopping: Male butterflies of some species look for mates by flying to the
top of a hill and patrolling or waiting there for the females to show up. If we
check the tops of low hills, especially from late morning to afternoon, we
may see butterflies that are hard to find in the surrounding country.
Patrolling: Males of other species fly back and forth along linear pathways,
such as trails or gullies, looking for females. They may come back time
after time to the same perches, allowing for repeated views.
Foodplants: Many butterflies are closely tied to the plants on which their
larvae feed. Hessel"s Hairstreaks are seldom seen away from Atlantic white
cedars; Square-spotted Blues are usually seen sitting on buckwheats. A
skilled lepidopterist is often able to find particular butterflies by learning to
recognize their larval foodplants.
THE BUTTERFLY"S LIFE CYCLE
The amazing process of metamorphosis — the butterfly"s transition from
egg to caterpillar to pupa to winged adult — is well known and fairly well
understood, but it is still rightly regarded as a miracle.
The process begins with the egg laid by the adult female on or
near the plants that will serve as food for the caterpillars. Most butterfly
caterpillars cannot survive on the wrong plants, so the adult"s choice of
where to lay her eggs is critically important. But given the right plant, the
caterpillar or larva (plural: larvae) is a little eating machine, and as it grows it
passes through about five stages, or instars, each one larger than the last.
Because the larva"s skin can stretch only so far, it sheds its skin each time it
passes to the next instar. The last time it sheds its skin, it reveals not a
larger larva but the next phase in its life, the pupa (plural: pupae).
The pupa, also called the chrysalis, is the stage in which the larva
is transformed into the adult butterfly. Unlike many moths, most butterflies
do not spin a protective cocoon; their pupa is smooth but often colored for
camouflage. When the development inside is complete, the pupa splits
open and the adult crawls out; after an hour or two for the wings to expand
and dry, the butterfly is ready for flight.
In cooler climates, butterflies have the challenge of surviving
through winter. Some pass the winter as eggs, others as partly grown
larvae or as pupae. A few overwinter as adults, emerging to fly about on
unusually warm winter days. But aside from such hibernators, and a few
large species such as Monarchs and longwings, most butterflies do not live
very long in the adult stage — a couple of weeks is a long life for a small
In some cases, a butterfly passes through all four stages in a
matter of weeks, and the whole cycle is repeated several times during the
year. In this guide we note how many generations, or broods, a species
may have per year. Many species have only one brood per year, and these
usually have short flight seasons. Some have fewer than one brood per year:
in the far north, where summers are short, some species take two years to
develop, hibernating through one winter as a small larva and the next winter
as a nearly full-grown larva; adults may appear only every other year.
Some butterflies found in northern climates cannot survive the
winter there in any stage. Instead, they invade northward every summer,
with some of their offspring surviving to move south in fall. These migrations
generally seem far more haphazard than those of birds, but so far they are
not well known.
HOW BUTTERFLIES ARE CLASSIFIED AND NAMED
The sheer variety of nature is wonderful, but it can also be very confusing.
To make sense of this diversity, scientists classify living things in categories
such as order, family, subfamily, genus, and species. All butterflies (and all
moths) are classified in the order Lepidoptera. The color-coded sections in
this guide are built around families or subfamilies of butterflies. For most of
us, the most interesting category is the species — the basic "kind" of
butterfly that we write on our list of sightings.
Species of butterflies: Whole books have been written to define exactly
what a species is. No definition will fit perfectly, because there are many
borderline cases, populations that appear to be in the process of becoming
species but are not yet quite distinct enough. In general, members of a
species are isolated from members of other species in terms of reproduction.
Different species often can interbreed (and may even produce fertile
offspring), but they generally don"t. For example, Crossline and Tawny-edged
Skippers (p. 324) look very similar to us, but they occur together over a wide
area without interbreeding, so they are clearly separate species. On the
other hand, the Red-spotted Purple and the White Admiral (p. 210) look quite
different, but they seem to interbreed randomly where their ranges meet,
forming a broad blend zone in the northeast; they are regarded as forming
just one species. Lorquin"s and Weidemeyer"s Admirals (p. 212) also may
interbreed in the narrow zone where they meet, but much less frequently;
they are still considered to be separate species.
Subspecies: Members of a species do not all look the same. Aside from
the kinds of individual variation mentioned on p. 9, they may vary consistently
from one place to another. These regional variations, if they are well
marked, may be formally described by scientists as subspecies. Subspecies
within a species will interbreed wherever their ranges come in contact, so the
divisions between them are not precise. In some cases a species will vary
gradually over a wide area (becoming gradually paler from east to west, for
example), and dividing this kind of clinal variation into subspecies is
arbitrary and not very useful. But if a subspecies has an isolated range and is
not in contact with other populations of its species, it may be very distinctive,
and may eventually become a full species.
In most cases we ignore subspecies in this guide, since the
differences are usually not obvious in the field. But if you develop a serious
interest in butterflies, you will discover a whole additional level of diversity
by delving into their subspecific variation.
Scientific names are applied to every known species. Mainly Latin or
Latinized Greek, these names are recognized by scientists working in any
language. The names are written in italics: Limenitis archippus is the
Viceroy. The first word is the genus: Limenitis. The Lorquin"s Admiral,
Limenitis lorquini, belongs to this same genus, so it is a close relative of
the Viceroy in spite of its different colors. If the scientific name consists of
three words, the third one is the subspecies. Limenitis archippus floridensis
is the dark subspecies of Viceroy living in Florida.
Standardized names: For some other groups of organisms, such as birds
and dragonflies, there are official publications (produced by committees of
expert scientists) that list all valid species and give standardized scientific
and English names for each. For butterflies, however, this has not been
done, and many different classifications and names have been used — you
might find the same butterfly called by three different names in three books.
To address this confusing situation, a committee of enthusiasts from the
North American Butterfly Association (NABA) has compiled The NABA
Checklist & English Names of North American Butterflies (second edition,
2001). Although this is not really an "official" list and is not followed by all
lepidopterists, it has proven to be tremendously useful for amateur butterfly
watchers. In this book, for the sake of convenience, we have followed the
NABA list in almost all cases.
Most people who use English names for butterflies today use
names that identify them only to species, not to subspecies, except in a
few cases involving populations that are very notable for some reason (such
as the San Bruno Elfin, an endangered subspecies of Moss"s Elfin).Unless
you plan to become deeply involved in taxonomic issues, it is usually easier
to stick with species names. However, some lepidopterists with a strong
interest in subspecies have suggested that each one should have its own
English name. We don"t follow this practice, but we should point out that a
list of suggested English names for all North American subspecies of
butterflies can be found online at http://tils-ttr.org/lepnames.html.
The unknown: In this guide we have presented all North American butterflies
in a way that reflects our current understanding of how they should be
classified. However, no one should assume that this is the final word.
Scientific understanding of some groups is still developing. For example,
the little Spring Azure was long regarded as one variable species found all
over North America. There is now good evidence that it is actually a complex
of species, perhaps seven or more. Similar complexes may exist within what
we now call the Square-spotted Blue, Dotted Blue, Juniper Hairstreak,
Common Ringlet, Mormon Metalmark, Mustard White, and others. We still
have much to learn about them.
As an example of how much remains unknown, as this book was
going to press, we received word of a new species described to science. It
was not a drab, small butterfly from a remote wilderness, but a large,
spectacular one in the eastern United States! This creature, the
Appalachian Tiger Swallowtail (P. appalachiensis), had been overlooked
because of its similarity to the Eastern Tiger Swallowtail; but it flies only in
spring, has no black form of the female, is larger than the spring brood of
Eastern Tiger, and has a narrower black and blue outer edge on the hindwing.
Opinions are still divided as to whether this is really a valid species, but it
looks promising, it hints at exciting discoveries remaining to be made.
OTHER ACTIVITIES INVOLVING BUTTERFLIES
Butterfly gardening: This is becoming tremendously popular in many parts
of North America, as people discover that they can add the beauty of
butterflies to their gardens. Whole books have been written on how to do it.
The details vary from one region to another, but the basics are the same
everywhere: plant some flowers for nectar to attract the adults, and plant
some foodplants for the larvae (caterpillars). The latter aspect is sometimes
neglected, but it is very important. By planting to feed the larvae, you can
actually increase local populations of butterflies, not just attract a few adults
that happen to be passing through.
And whatever you do, don"t spray pesticides in your garden.
Butterflies are insects; pesticides kill insects (along with lots of other
things). A living garden with butterflies and bugs and other creatures may
have holes chewed in the leaves, but it will still be far more beautiful than
a "perfect" garden that has been sprayed and poisoned into sterility.
Butterfly photography: While bird photography usually requires bulky,
expensive telephoto lenses, butterflies can be approached closely and
photographed without much special equipment. A good macro lens is
needed for the smaller species, and flash is helpful. Our colleagues Rick
and Nora Bowers, who contributed more images to this book than any other
photographers, almost always use artificial light — a ring flash or a bracket
with two flash units — to get the best detail, color, and depth of field. But in
some situations it is possible to get very pleasing shots with natural light.
Digital cameras have added a new dimension to butterfly
photography. They are improving rapidly, and the latest models do an
amazingly good job of capturing sharp closeups. We (Bowers, Brock, and
Kaufman) are all still using film and then making digital scans from the
slides, but we suspect that our conversion to straight digital photography is
not far off.
The field is wide open for aspiring butterfly photographers. While
Monarchs and a few others have been photographed many times, there are
very few images available for many of the skippers, hairstreaks, and others
(as Nora Bowers discovered in trying to track down all the images for this
guide). If you seek out some of the less common butterflies, you may wind
up taking the world"s best photos of those species.
Visiting butterfly houses: In recent years, live butterfly exhibits have opened
in many parts of North America. While we generally prefer to search for
butterflies in the wild, these exhibits can be fascinating places to visit. They
usually feature large, showy species from tropical regions. Often
the "livestock" is supplied by firms in the developing countries of the tropics,
and these companies provide local people with a good income and an
incentive to preserve some pieces of natural habitat for butterfly populations.
Therefore, in addition to their educational value for visitors, these butterfly
houses are often supporting good social and conservation causes as well.
Conservation: The most important thing you can do with butterflies is to
help preserve their wonderful diversity. One of our main objectives in writing
this guide was to inspire more people to notice and appreciate butterflies so
that there would be more support for their conservation.
The main threat facing butterfly populations is loss of habitat.
Some of our most beautiful butterflies, such as the Regal Fritillary and the
Hermes Copper, have disappeared from much of their former range because
their specific habitats have been destroyed. Preserves for butterflies do not
have to be very large, but without them we will certainly lose some species.
Pollution of their surroundings, especially with insecticides, poses
another problem. Widespread, indiscriminate spraying for gypsy moths has
undoubtedly killed billions of butterflies, along with countless numbers of
our beautiful silk moths and others. Several butterflies in southern Florida
have become quite rare in recent years, and we have to wonder whether
heavy, continuous spraying for mosquitoes may have been a factor.
Uninformed persons sometimes imagine that butterfly collectors
pose a threat also, but there is scant evidence for this. During an average
week in summer there are probably more butterflies killed by cars on
American roads than the total taken by all the collectors in history. For any
would-be protectors of butterflies, harassment of net-wielding lepidopterists
is a waste of time; habitat protection is a more worthwhile effort.
Two conservation groups especially deserve support.
The Xerces Society, 4828 Southeast Hawthorne Blvd., Portland,
Oregon 97215. Named for the Xerces Blue, a butterfly that was driven to
extinction by habitat loss in the 1940s, this organization works for the
conservation of butterflies and other invertebrates.
The Nature Conservancy, 1815 Lynn Street, Arlington, Virginia
22209. This pragmatic organization protects habitat in a very direct way, by
buying it. The Nature Conservancy has many good biologists on staff,
including some expert lepidopterists, and in working to save particular
habitats they take into account the needs of rare butterfly species.
Relations between watchers and collectors: We assume that most users of
this guide want to watch butterflies, not collect them. Collecting requires a
lot of equipment and a lot of work, and most people find it easier just to enjoy
live butterflies in the wild. However, these new watchers or "butterfliers"
should recall that essentially all of our knowledge of butterfly classification
and distribution is based on the work of collectors. They are the pioneers
and discoverers, and their work is not finished.
Not all butterflies can be identified in the field, and collected
specimens are essential for study. Species of butterflies new to science are
still being discovered, and they must be scientifically documented before
their habitat can be protected, so collecting is an essential part of both
science and conservation. We have no evidence that collectors have ever
caused the extinction of a butterfly species — but a strident anticollecting
attitude might result in some species going extinct without having been
Copyright © 2003 by Hillstar Editions L.C. Reprinted by permission of
Houghton Mifflin Company.
Library of Congress subject headings for this publication: Butterflies North America Identification, Butterflies North America Pictorial works