The Hummingbirds of California

Home , Calliope hummingbird, Hummingbird, Rufous

THE AU K-

A QUARTERLY JOURNAL OF

ORNITHOLOGY.

Von. xn•v. JunY, 1927. No. 3.

COMMENTS ON THEIR •IABITS AND CHARACTERISTICS.

BY ROBERT S. WOODS

(PlatesXV-XVII) ALTnOVGn the Hummingbirds comprise one of the largest families of American Birds, including some five hundred species, but nineteen have been found within the United States, and of these only one occurseast of Texas and the Rocky Mountains. Of the nineteen,two species,both of whichwere taken in California, are thought to have been mere adventitioushybrids, while nine others are restricted to within about 100 miles of the Mexican border in Arizona, New Mexico and Texas, several of these latter beingrepresented only by casualvisitants or stragglersfrom their true homesfarther to the south. Of the remainingeight which may be consideredmore definitelya part of our fauna, six species are of commonoccurrence over large portionsof California, while a seventh has also been found within the borders of the State. Before proceedingto the more specificdiscussion of the Cali- fornia Hummingbirds,it is interestingto note that althoughgreen is the prevailing color on the throats or other luminousparts of the plumage of the Mexican, Central American and West Indian species,occurring oftener than all other colors combined, this coloris not foundon the throat of any of the eight Hummingbirds whoserange lies largelywithin the United States. In four of these the gorgetis red, in two it is reddishpurple or rosepink and in the remainingtwo, violet. In only five or six others of the 140 297 TIt• Av•, Von. XLIV PLATE XV

1. FEMALE COSTA'S HUMMINGBIRD FEEDING YOUNG. 2. NEST OF COSTA'S HUMMINGBIRD-•BITS OF PAPER USED FOR ORNAMENT. NEST•ATTACHED TO UPRIGHTSTUB BY COBWEBS. 298 Woo.s,Hummingbirds ofCalifornia. JulyAuk species(exclusive of subspecies)listed by Mr. Ridgway in 'Birds of North and Middle America' doesthe red color appear,and in none of the 30 speciesliving in or near the Panama Canal Zone. The impressionis thus gained that northern latitudes must in someway be conduciveto the developmentof red areas in the plumage of the Trochilidae, and this impressionis strengthened when we consider that the Rufous and the Ruby-throated Hummingbirds, which reach the highest latitudes in summer, and likewise Anna's and Allen's'Hummingbirds, which winter farthest north, all have red gorgets,while the Rufous Humming- bird, the hardiestpioneer of all, is unique in the reddishcolor of its back as well. Despite the predominanceof yellow flowers, pureyellow is entirelylacking in the plumageof North American Hummingbirds. However scanty in numbersas comparedto the multitude of speciesinhabiting suchcountries as Ecuador, Colombiaor even Costa Rica, with respectto brilliancy of coloringthe California Hummingbirdsneed not suffer by comparisonwith. the tropical species,many of whichare of plain andsomber garb. Mr. Ridgway declaresthat "of all the gorgetedHummingbirds by far the finest are the two speciesof the genusCalypte which inhabit parts of Mexico and California and the single one found in Cuba," and quotes Mr. Gould to the effect that the Rufous, Costa's and Anna's Hummingbirds "are unequaled for the rich metallic brilliancyof certainparts of their plumage,by any othermembers of the family." (Report of NationalMuseum, 1890, pp. 301 and 336.) Omitting from considerationthe very rare Floresi'sand Violet- throated Hummingbirds,thought to have been hybrids of Selas- phorus and Archilochus,respectively, with Calypte anna, the mannerof occurrenceof the variousspecies within the State of Californiamay be briefly indicatedas follows: Archilochus alexandri. BLACK-CHINNED HUMMINOBIRD.--Summer visitant to southern California and northward on both sides of the Sierra Nevada. Absent from the northern coast region and the Santa Barbara Islands. Calypte costae. COSTA'SHU•a•t•NOB•RD.--Summer visitant to the mesas and deserts of southern California, ranging as fax northward as Santa Barbara and Inyo Counties. Vol. XLIV1 1927 ! WOODS,Hummingbirds of California. 299

Ca•rpt• •111a. ANNA'SHUMMINOBIRD.--Resident, mainly west of the high mountains,northward through the San FranciscoBay regionand the SacramentoValley. Selasphorusrufus. RUFOUSI{UMMINOBIRD.---Spring migrant through the valleysand foothills of thePacific slope; late summerand fall migrant, principallyalong the mountainranges. Selasphorusalleni. ALLEN'SI-IuMMINOBIRD.---SpI•ng and summer visitantto the humidcoast belt, as far south,locally, as Santa Barbara andVentura Counties. Resident on theSanta Barbara Islands. Migrant throughthe southernend of the Sta•e. Selasphorus platycercus. BROAD-TAILEDI-IUMMINOBIRD.---Summer visitantto the highermountain ranges of easternInyo and Mono Counties. 8tellula calliope. CALLIOPE HU•MINGSIRD.--Summer visitant to the Sierra Nevada and the higher mountainsof southern California. Springmigrant alongtheir bases.

OBSERVATIONSIN THE SAN GABRIEL VALLEY. A dozenyears' experiencein raisingoranges and other sub- tropicalfruit at Azusa,California, not far from the mouth of the San GabrielCanyon, in Los AngelesCounty, have giventhe writer an opportunityto becomemore or lessfamiliar with six of the Californianspecies of Hummingbirds,which gather in con- siderablenumbers in and aboutthe orangegroves during the bloomingseason, which usually coincides with the spring migration of mostof thesespecies. I have seenall six herewithin lessthan 30 days,and at timesin the monthof Aprilall but Allen'sHum- mingbirdappeared to bepresent together. Allen'sHummingbird is not very commonin thislocality, but occasionally,from the last of Januaryuntil the vernal equinox, a metallic screechingsound draws one's attention to a male of this speciesas it tarriesbriefly among the flowers. The Rufous Hummingbirdis the next of the'migrants to appear,usually arrivingearly in Marchand leaving late in April Duringpart of thistime it is the commonestspecies. My earliestrecord for the Rufousis February 17 (1926) and the latest for the spring migration May 1 (1924). The adult male is only an occasionalvisitant on the southwardmigration in late summer,though the females,or more probablyimmature birds of both sexes,are seenmore frequently.Costa's Hummingbird is irregular in,its arrival,but may be lookedfor at any time after the middleof March (the 300 Woo.s,Hummingbirds ofCalifornia. JulyAuk

earliestwas noted on March 16, 1923), and stays until June or the first of July, beingthe only specieswhich I havefound nesting about the grove. The Black-chinncdHummingbird is a very transient visitant in the month of April, but returns after the breedingseason, sometimes as early as the last of June, and is likely to remain in the Valley for a month or more after the Costa's have departed. The CalliopeHummingbird makes only a short stay, beingpresent in small numbers,if at all, for a week or two in April. Anna'sHummingbird is apt to be seenat any season, exceptpossibly in midsummer,but never in abundance. The spring migrants, and likewise Costa's Hummingbird when it first arrives,are almostconstantly in a state of activity, so that it is often difficultto obtain more than a fleetingglimpse of them as they chaseone another about. At these times there appearsto be a great preponderanceof males, which is partly accountedfor, no doubt, by the quieter and more retiring habits of the females. Anna's Hummingbird, being a resident, does not seem to share to any great extent in the feverish activities of the migrants,but for the mostpart sitsaloof upon a deadtwig at the top of somebush, and as the seasonadvances the male Costa'salso follows that example.Hummingbirds fe•l theheat, and on hot days they are likely to abandontheir exposedperches and seeka shadyspot. A highwind alsowill causethem to remain in a shelteredplace, but on a cloudy,misty day they are apt to be much in evidence. A Hummingbirddarting about at top speed.is not a convenient subject for identificationby the use of the usual keys; hence, a more intimate knowledge of certain habits and characteristics is often of assistance.The gradationsin size are not distinct enoughto be of great serviceas a meansof recognition,though when the Anna'sand CalliopeHummingbirds are seentogether the contrastis rather striking. In the Black-chinnedHumming- bird it is particularlyhard to make out the color of the throat, becauseof the comparativedullness as well as the restrictedarea of the metalliccoloring. The male of this speciesmay alwaysbe known,however, by the square-cutgorget and the generalblackish colorof the sidesof the head, in sharp contrastto the white of the neckand the conspicuouspostocular spot. THE AUK, VOL. XLIV PL.tTE XVI

1. BLACK-CHINNED HUMMINGBIRD. 2. COSTA•S HUMMINGBIRD. NEST OF COSTA'S HUMMINGBIRD PARTLY SUPPORTED BY LEAF WHICH BECAME DETACHED LEAVING IT HANGING BY ONE EDGE. Vol. XLIVI 1927 ] WOODS,Hummingbirds of California. 301

A pronouncedmetallic screeching or rattling soundaccompanies the fiigh• of the maleRufous and Allen'sHumming birds and in a slightly lesserdegree that of the male Black-chinnedHumming- bird. The flight of the CalliopeHummingbird is not definitely metallic,but sometimesis characterizedby a shrill,strident quality not exhibitedby any of the other kinds. The male of this species is able to produceat will a loud buzzinglike that madeby a large fly entangledin a spider'sweb. I have seenone leave his perch repeatedlyand hover near by to buzz in this way, apparentlyfor his own entertainment. The only sound ordinarily heard in connectionwith the flightof the maleAnna's and Costa's Humming- birds,•s with that of the femalesof all species,is a soft, deephum which increasesin volume and pitch when the bird accelerates its speed,and has at timesa certainsilken rustling quality. If the male Anna'sand Costa'sHummingbirds lack distinguish- ing peculiaritiesof flight, they are the most easily recognized through their vocal utterances. The squeaky, metallic song of the Anna'sHummingbird, in which it indulgesquite persistently with little regard for season,is a sure indication of the species, while the presenceof a Costa'sHummingbird is frequentlyan- nouncedby the two-or-three-syllabledwhistling call with which he greetspassing members of the tribe from his perchor salutes his mate as he hovers before her. The young males begin practicingon thesewhistling notes, which are doubtlessamong the highest-pitchedsounds audible to the humane ar , beforethey have yet 'attainedtheir brilliant gorgets,with resultsthat some- timesrather resemble the songof theAnna's Hummingbird, though muchfainter andlesssustained. The other speciesseem less given to vocalization,aside from the feedingnote and the excitedtwitter- ing accompanyingthe' chase, which are commonto all speciesand both sexes alike. A male Hummingbird,when too far away to be distinctlyseen, can often be identifiedby the manner of its "nuptial flight," so called;or evenwhen not visible,by the utteranceaccompanying such flight. It may be questionedwhether the term "nuptial flight" is correctlyused in this connection,as the Hummingbird frequentlydirects his attentionon theseoccasions toward one of a different speciesor, as often as not, toward a bird of another 302 Woo,s,Hummingbirds ofCalifornia. [[July Auk sort entirely. The fact that this maneuver is practiced only by the adult males,however, would imply some sexualsigni- ficance,so for lack of a more accuratelydescriptive name the presentone may well be retained. Perverselyenough, the females, whichare often so difficultto identify by their appearance,have no suchdistinguishing characteristics of voiceor flight. The mostelaborate nuptial flightis that of theAnna's Humming- bird. When carried out in its completeform the bird mountsal- most vertically to a lofty height, then suddenlydescends with terrific speed;when within a short distanceof the object of its attentionit turns rather sharplyupward again, at the sametime givingutterance to a loud, explosivechirp resemblingthe bark o• a groundsquirrel, and returnsto a point directlyoverhead, where it.pausesfor a few secondsto renderits song,after which it again ascendsmore slowlyand repeatsthe processuntil it tires or the other bird departs,with the Hummingbirdin hot pursuit. The Costa'sHummingbird, instead of makinga moreor lessabrupt turn, sweepsthrough a great arc to describean immenseletter U, then passesoverhead to shootdownward again, either from the same directionor at a new angle. A continuousshrillwhistle or miniature shriekaccompanies most of the downwardcourse and part of the upward--in other words, that part of the circuit in which the velocity is highest. This Hummingbird often ends his seriesof loops by darting away at high speedin an erratic, zigzagging flight. The CalliopeHummingbird also performsa nuptial flight of rather similarcharacter, but in form tendingtoward the hyper- bolic and markedat the lowestpoint by a curiouslymuffled yet explosivesqueak, quite characteristicof the species. In additionto this lofty type of nuptial flight,which seems to be sharedto someextent by all the species,other formsare usedby certain of them. Allen's Hummingbirdflies rather slowly back and forth along a path such as would be describedby a giant pendulum,with a sort of lateral writhing movementof the body and extended tail and a vibratory metallic noise, but without vocal sound. Again it will poiseitself closein front of another bird and rapidly shuttle to and fro sidewisethrough a spaceof perhapsa foot or two. My observationof the Allen'sand Rufou's Hummingbirdshas not beenextensive enough to determinewhether Vol. XLIVI 1927 ] WOODS,Hummimjbirds of California. 303 their practicesin this respectare identical, but a closesimilarity would be expectedfrom the nearnessof their relationship. During its stay in southern California, however, the 'type of nuptial flight favored by the Rufous Hummingbird is a swoopingdive like that of the CalliopeHummingbird, punctuated at thebottom .of its courseby what might be describedas a tremulant squeak or a rapid successionof about four thin, vibrant notes. This sound, like that of the Calliope Hummingbird, is of so peculiar a nature and so different in quality from the normal voiceof the bird that the only reasonfor assumingthat it is producedby the throat rather than the wingsis the unmistakablyvocal origin of the soundin the caseof someof the other species. The shuttlingof the Black-chinnedHummingbird, which follows a path like a narrow figure 8 lying on one side, has often been mentionedin accountsof the species. Its other form of nuptial flight most closelyresembles that of the Rufous Hummingbird, just described, but the vocalization is more prolonged and of rather different character---a long-drawn, pulsating, plaintive, liquid note, probably the most pleasingutterance of any of our Hummingbirds. The heavy droningsound of its flight, so notice- able. in the shuttling movement, is heard in this case only while momentumis first being gained on the downwardswing. The shuttling flight, it may be noted,'is practicedalmost solely by thosespecies in which the wingsof the male are speciallymodified for noise-makingpurposes. To see an Anna's Hummingbird, hoveringmotionless in the air with body nearly horizontal,suddenly begin to rise rapidly and vertically,as if by a reversalof the forceof gravity, is to obtain someidea of the bird's remarkablemastery of the air. Despite the Duke of Argyle's postulate that "no bird can ever fly back- wards," the ability of the Hummingbirdto fly backwardsor in any other directionit wishescan hardly be questionedby onewho has watched an aerial tilt betweentwo of thesebirds, during which they advanceand retreat at every angle,performing all manner of evolutionswith the appearanceof utmost ease. In the matter of flight, the differencebetween work and play seemsto be well recognizedby the Hummingbirds. Consideringthe great amount of unnecessaryflying whichthey do, it is amusingto seeone hang 304 Woo.s,Hummingbirds ofCalifornia. JulyAuk almostupside down rather than use its wingswhile probing a flower. No one who possessesan appreciationfor color can tire of studying the changinghues of a Hummingbird's throat. The statement has been made by an eminent naturalist that the luminousreflection appears only as a singlespot ever varying in positionwith the movementsof the bird. But if an Anna's Hum- ming bird, for example,is vieweddirectly from the front, with the light at the observer'sback, the whole head and gorget glow in their full resplendence. Sometimeswhen it approachesand hoversin front of one, as it is apt to do, the effect is as if a coal of fire was suspendedin mid-air. The color of the head and throat of Anna's Hummingbirdis lesschangeable than are the colorsof somespecies, but in certain aspectsthe beauty of the brilliant rose-pinkgorget is enhanced by a border of richest gold. Costa's Hummingbird, on the otherhand, shows a widevariation in its coloringaccording to the conditionsof the light. The headand gorggt.ofa singleindi- vidual will sometimesappear violet-blue and at other times magenta,approaching the color of Anna'sHummingbird. Unlike the latter species,the coloringof Costa'sHummingbird is not exhibitedto the best advantagewhen directly reflecting the brightest rays of the sun, as the intense brilliancy causesa palingof thedelicate violet tints. In a morediffused light rich blue and red high tints may often be observedon different parts of.the head at the same time. The gorgetsof the Rufous and Allen's Hummingbirdsare normally of an intensescarlet, but at someangles appear as if pure burnishedgold. The reddish-purple throat of the Calliope Hummingbird varies little in shade, but the odd color pattern and serrated edgesof its gorget, together with the interestthat attachesto it from its positionas the smallest of our birds, make it by no means the least attractive of the Hummingbirds. Numerous statements, some of them directly contradictory, have beenmade regardingthe dispositionand comparativeaggres- sivenessof the severalspecies. From my own observationI have been unable to detect any constant differencesin this respect, and believethat thosenoted by othersmay perhapsbe attributed

Vol,1927 XLIV] ] WOODS,Hummingbirds ofCalifornia. 305 to season or circumstances. The Calliope Hummingbird, for example,which has been describedas retiring' and peace-loving, takingno part in the contestsof the largerspecies, does not, in fact, hesitateto attack'Anna's Hummingbird and whenchased away {mme•liatelyreturns to renewthe challenge.On the other hand, I have'seen' Allen's Hummingbird,to 'which Mr. Allen ascribedunusual aggressiveness, meekly turn tail whenan Anna's or a.Rufous Hummingbird resented an infringementof its territory. (Reportof NationalMuseum, 1890, pp. 349 and357.) In the sameconnection Mr. Allen referred to the great activity of Allen'sHummingbird, as contrasted with the Rufous. While passingthrough the San Gabriel Valley' Allen's Hum- ming bird is indeedvery active, thoughhardly more so than the other springmigrants; but on Santa Catalina Island during the nesting seasonthe same restful dispositionis apparent that is shownby other speciesunder similar conditions. There the males remain perchedon wires or exposedtwigs for quite long periods and appear to confine themselveslargely to certain restricted areas when not feeding. Towards evening, like other species, they make shortsallies in F•ycatcherfashion after passinginsects too minute to be discernedby the humaneye. As to themotlve for the frequentcontests and pursuits, it is of courseimI•ossible to speak with certainty, though there is no doubt that a Hummingbird,having laid claim to a particular feedingground, resents any competitionwithin its' limits. These vestedrights'seem to be recognizedby the intruders,who seldom tarry to dispute possession.'In general,however, and especially during•migrationsand amongthe youngbirds in midsummer,when suchactiviiies are most pronounced,they impressone as being mainlythe res{litof exuberanceof spiritsand a sportivedisposition. This is borneout by the lack of injury'and, usually,of any contact betweenthe contestants;also by fhe fact that the diversionseems 'to be equallyenjoyed by pursuerand pursued,as the latter will often return and' hover in front of the former as an invitation-to anotherrace. Sometimesa soundis heard as of the dash of wings, but by closeattention it Will'be seenthat this noiseis often pro- ducedwhen the birds are entirely separatedand occasionallyby a solitary individual,'probably by striking the wings togetherover the back. 306 Woo.s,Hummingbirds ofCalifornia. l! July Auk

A sickHummingbird, however, seems to receivelittle sympathy from its fellows. ! had wondered what would be the result if a Hummingbirdquietly refusedto take part in these skirmishes, and on a certain occasion when one of the three or four which were frequentingthe gardenseemed to be sick or injured and hence averse to unnecessaryactivity, I was able to note the outcome. Another,apparently a youngmale Black-chinnedHummingbird, with a singledark spoton the throat,would shuttle back and forth in front of it as it sat on sometwig, darting at it at the end of every few oscillations,sometimes striking it with its bill, until the unfortunatebird would be compelledto take flight. ! am convincedthat the Hummingbird'sactions towards other birds are usuallyfree from hostileintent, even whennear its nest. As an indication of this, I have known a Dove to make its nest in the same tree and within a few feet from where a Hummingbird was rearingher young,which would hardly have beenlikely had the Hummingbird maintained an unfriendly attitude. The Hummingbird'spursuit of other'birds seems to be due to its love of the chaseand dependsupon its mood,as it often ignorestheir near approachand evenallows itself to be bulliedby them without showingresentment. Similar deductionsmay be drawn from the lack of fear evidencedby birds as small as the Goldfinches,though the Hummingbirdcould undoubtedlymake itself disagreeably felt if it were so inclined. Some of our Hummingbirdsseem to be in a measure,at least, independentof the presenceof flowers,since Anna's Humming- bird managesto subsistat times when, on accountof severefrosts, flowers are extremely scarce. During the nesting seasonit has seemedto me that the female Costa's Hummingbird visiksthe flowers much less than does the male.' At such times the female may often be seenbuzzing about inside non-floweringtrees and shrubs. While the searchmay be primarily for cobwobsor other nesting material, numerousminute insects and spiders might incidentallybe obtained. Hummingbirdsare attracted to flowersinitially by theircoloring: A bunch of carrots will sometimes arouse the interest of a Hum- mingbird, and ! have seen one probing dusters of bright orange Crataegusberries. But when once establishedin a locality they Vol.1927 XLIV] ] WOODS,Hummingbirds ofCalifornia. 307

will habitually passover someof the showiestflowers as unsuited to their uses,seeking out others,perhaps much lessconspicuous, which minister to their needs. An important addition, from the Hummingbird's standpoint, to native and cultivated flowering plants isthe Tree Tobacco(Nicotiana glauca) (Pl. XVII). Thisrank- growing,drought-resistant South American shrub, now naturalized and widely distributedin southernCalifornia, bears a profusion of tubular flowersthroughout the entire year. In connectionwith this plant may be seenan instanceof the discriminationexercised by Hummingbirdswhen food is plentiful, in that they ignorethe yellow mature flowers,probing instead the greenishnewly opened blossoms. Costa's Hummingbird, for some reason, seems less partial to the Tree Tobaccothan do the largerspecies. Runningwater drawsthe attention of Hummingbirds,but they fear to enter it if it is of any appreciabledepth, thoughthey will sometimesdrink while hoveringover it. Most of their bathing is done in the dew collected on the foliage of plants. They will occasionallyhover in a fine spray when available, and in winter I have seenAnna's Hummingbird alight on the lawn under the spray and indulgein a very thoroughbath. As with other birds, early morningand coolweather are the favoredtimes for bathing. Owing to their close relationshipin structure and habits, the nidificationof all of the above mentionedspecies is very similar, and the variationsdue to individuality or adaptation to external conditionsare often greaterthan the constantspecific differences. The following account of the nesting of Costa's Hummingbird will thereforeapply in manyrespects to the otherkinds as well.

FAMILY LIFE OF COSTA'S HUMMINGBIRD The family life of the male Costa'sHummingbird may be easily disposedof with the simplestatement that he has none. No male Costa'shas ever in my experienceshown enough interest in family affairs to indicate his relationshipwith any particular brood. His mate, however,amply makesup for his deficiencies and findsno difficultyin managingthe householdwithout his aid. The admirably delicate architecture of this Hummingbird's nest is well known and need not be enlargedupon here. Those which I have examined were about one and one-half inches in 308 woo.s,Hummingbirds ofCalifornia. t[ JulyAuk

outside diameter and were constructed with a framework of fibers, small flexiblestems and piecesof string affixedto the supporting branchby meansof cobwebs,and with a thick, soft lining of plant down and small feathers,the exterior being ornamentedwith numerousbits of bark, paperor miscellaneousdry vegetablematter securelybound thereon with cobwebs. Much of the soft material, as well as the ornamentation of the exterior, is added after the eggsare laid, so that the latter may be almost hidden for a time. This material is compactedby treading and turning about in the nest, the bill often being thrust beneathto rearrangesome part of it. The quality of the constructionvaries considerably. Some of the nestsare soflimsy that after the youngare partly grownthe nest becomes flattened out or broken down at the sides. Others are so solidly and compactly built that they retain their shape with no appreciablechange as long as they are in use and for many months afterward. The first stage of the construction requiresbut two or three days, after which,however, an equal periodof inactivityis likely to ensuebefore the first eggis laid. At Azusa, California, the nests have been found at heights rangingfrom two to nine feet, but most commonlyin the neigh- borhood of four feet. When a bush or small tree is selected, as is frequently the case, the nest is almost invariably located at a height of approximatelyone-half of the total height of the tree, but near the outside rather than the center, and in a position from •which a reasonably clear outlook may be obtained. On this accounttrees of dense,leafy growth, suchas an orangetree in thrifty condition,are not favored. The great majority of the nestsdiscovered in this particular grove were placed in avocado trees or in bushesof the Feijoa sellowianaor Paraguay Guava, whichtogether made up a cornerof the orchard. If in a largetree, the nest is usually on a small twig near the end of a projecting lower limb. In an orchard under cultivation the latter location is a very hazardousone, sincethe nest is apt to be wreckedby the passageof team or implements,and furthermoreis subject to destructionby strong winds or by the droopingof the slender twig underthe increasingweight of the young. It may be assumedthat the scantheight at which this species prefersto nest is the resultof an inheritedhabit due to the fact Vol. XLI¾1 lo27 I Woo•)s,Hummingbirds of California. 3O9

that large trees were originally absent from much of its range. The dangerof injury through the tilling of the soil is, of course, somethingthat the bird's instinet couldnot be expectedto provide against, and the failure to recognizethe possibility of disaster from wind or the saggingof the supportingtwig might be accounted for by the fact that the natural vegetationof the arid regionsis inclinedto be more or lessrigid, but poor judgment is sometimes showntoo in building upon an inadequateor unstablebase, which may in time result in the tilting or entire looseningof the nest. (P1. XVI) The nest is frequently, and wisely, placed on a fair- sizedhorizontal branch, at the base of a twig or spur, to which it is securelyahehored. Oeeaslonallya limb an inch or more in diameter is chosen,which adds to the stability of the nest, but wouldrender it moreaccessible to climbingpredatory animals. The eggs,as with all Hummingbirds,are two in number, white, tinged with pink when freshly laid, and oblong in form. An interval of about two days separatesthe laying of the eggs. In- cubation, in every ease that I have observed,has begun with the laying of the first egg, and the young are usuallyhatched out a day or more apart. If we are to accept the widely differing periodsreported--from nine to eighteendays--the time of incubation must be regarded as extremely variable. On account of absencesI have not succeededin collectingas full information on this subjectas couldbe desired,but data of varying accuracy obtained during five successiveyears indicate that the normal incubationperiod for Costa'sHumming bird in the San Gabriel Valley is about sixteen days, lengtheningin eertaln instancesto as much as eighteendays, but never falling below fifteen days. These figuresdo not differ materially from the time of seventeen days given by Mr. Dawson for Anna's Hummingbird, whose incubation he regarded as lasting "a good deal longer than is customary with our other Hummers." (Birds of California, p. 942.) This is a longertime than is requiredby the eggsof the commonerpasserinc birds, notwithstandingthe larger size of the latter. There is a remarkabledifference in the shynessof the various individualswhen on the nest. Somewill leaveas soonas a person comesinto sight, perhapsforty feet away; others will permit one 310 Woo.s,Hummingbirds ofCalifornia. •Auk[July

to reachwithin a few inches,or possibly,with care, even to touch them, without leaving the nest. The shyer ones, however, are inclinedto hold to the nest more closelyas the incubationad- vances,and especiallyaround the time of hatching. Most of them, thougheasily frightened from the nest, will soonreturn if one standsquietly a few feet away, a decidedreversal of the tendenciesof the majority of nesting birds. Apparently the Hummingbirdrequires but little time for the procuringof food, sincethe eggsare seldomfound uncovered. The growingperiod of the youngis even more markedlypro- longedthan is the incubation. Someeight broodsfor which the time was determinedwith fair accuracyremained bf the nest from twenty to twenty-threedays after hatching, with all but two approximatingthe higherfigure. A similar periodwas sufficient for a pair of Western ChippingSparrows not only to rear their young but to incubatetheir eggsas well. At the samelocality the youngof suchbirds as the HouseFinch, Green-backedGold- finch, Western Lark Sparrow, Anthony's Towhee and Western Mockingbirdwere found to leavethe nestin from ten to sixteen days, accordingto individualvariations. The Phainopeplamore closelyapproached the Hummingbird'stime with nineteendays, the incubationperiod being sixteen days. Taking a speciesmore nearly comparablein size to the Hummingbird,two broodsof Black-tailedGnatcatchers occupied their nestsnine and ten days. Whether two or only one youngHummingbird was beingreared madeno differencein the rate of growth. It is possiblethat they developmore rapidly in other districts,since Mr. Dawson,who has observedthis speciesnear Santa Barbara, statesthat "under favorablecircumstances the youngbirds fly in fromten to fourteen days" (Birds of California,p. 953); but in view of the notable uniformityof the Azusarecords this variancewould seem quite remarkable. Even more pronouncedthan in most other altricial birdsis the contrastbetween the newlyhatched Hummingbird and its parents. Th• minutegrnb-like creature is blackabove and brownishbelow, with the body entirely bare exceptfor a row of yellowishfilaments alongeach side of the medianline of the back. The bill is yellov( andtriangular, its lengthbeing but slightlygreater than its width Vol. XLIV1 1027 ] WOODS,Hummingbirds of California. 311 at the base. The eye-socketsproject beyondthe baseof the bill. Until about the sixth day, when the pin-feathersbegin to appear, the most noticeablechange, aside from the increasein size, is the graduallengthening and darkeningof the bill. The first part of the young Hummingbirds'lives is spentstretched out on the bottom of the nest, but after a time they becomelonger than the interior of the nest, so that they are gradually forced to raise theirheads against its sidesuntil at ones. tage of theirgrowth their bills are pointingdirectly upward. After this their development is more rapid, and when they begin habitually to hold up their headsand assumean alert appearance,they are nearly ready to fly. The last few days beforeleaving the nest, the young birds frequentlyexercise their wings,sometimes perching on the edge of the nest for freer action. 1•inallya time is reachedwhen, con- trary to their formerindifference, they are likely to leaveon very slightprovocation. A personmay be quietly standingand watch- ing them whenas with one impulseboth springfrom the nestand fly in different directions.' It sometimesso happensthat the youngerof the two is thus inducedto venture forth beforeits wingsare capableof sustainedflight or of enablingit to obtain a foothold in a tree. On two such occasions I found that the bird might readily be pickedup and whenrestored to its nest gladly settleditself to await moreadequate strength. The youngHummingbirds are fed by regurgitation,of necessity, at intervalsof abouthalf an hour. The feedingrequires perhaps half a minute in all and is accomplishedby a violent pumping process,with the bill thrust deep into the open mouth of the young bird. One would not judge that the slow growth of the Hummingbirdwas due to inability to supplysufficient food, since the mother, thoughbearing the entire care of her offspring,does not seemoverworked, but has plenty of time to rest, preen her plumageand engagein skirmisheswith otherHummers. Her care of the youngcontinues for sometime after they have left the nest. Then their call for foodmay be heardat intervals,a shrillcheep resemblingthe cries of other young birds rather than the voice of the adult Hummingbird. After the younghave attained their full growthin other respects,they may still be recognizedby the comparativeshortness and straight,subulate formof the bill. 312 woo.s,Hummingbirds ofCalifornia. t[Auk July

In no casewithin my knowledgehas a secondbrood been sue- eessfullyraised, and only twice have eggsbeen found late enough in the seasonto have representeda possibleattempt to do so. In 1922 a set of eggs was laid about June 6, but was abandoned before hatching. In 1923 the seasonwas unusually early; the first male Costa's Hummingbird was noted on March 16, and fledgedyoung were seenby May 7. Later a set of eggswas dis- coveredwhich hatched about June 2, but one of the nestlingsfell to the ground,while the otherfailed to developproperly and was unableto fly even after thirty days in the nest. The following year a broodwas still in the nest as late as July 4, but the nesting had begunmuch later than the previousyear andthis was doubt- lessthe secondattempt of a parent who had lost her first set of eggs. The malesdo not feel it necessaryto await the outcome of their mates' labors; in 1924, followinga very dry winter, the Costa'sHummingbirds nested in quite large numbers,but very few males were to be seen'after the early part of the season. For the purposeof affordingan ideaof the percentageof success and the causesof failure, a table is appendedsummarizing the resultsof severalyears' observations of the nestingof the Costa's Hummingbird. In order that the proportionsmay be more truly representative,only those nestshave been includedwhich. •vere discoveredbefore the eggs were hatehe& The figuresin each easeindicate the number of nests,without referenceto the number of eggsor young contained. 1922 '23 '24 '25 '26 Total Number of nests containing eggs 2 6 9 9 3 29 Destroyed in cultivation or by wind 3 2 5 Both eggsdisappeared I 1 Abandoned before hatching I I 2 4 One egg only hatched I I 2 4 Both eggshatched I 4 5 2 3 15 Died or abandonedafter hatching I I I 3 Destroyedby animals I 1 Lost by tilting or looseningof nest I I 2 Failed to develop properly I 1 One young fledged I I 2 I 5 Two young fledged I 2 2 i i 7 Though the initial figuresin the table do not representthe entire numberof pairs nestingin the area, they probablyfurnish Vol.1927 XLIV] ] WOODS,Hummingbirds ofCalifornia. 313

a fairly accurate index to the relative yearly abundance,with ßthe possibleexception of 1922,when the searchfor nestsmay have beenless systematic than in succeedingyears. 1924and 1925were exceptionallydry seasons,which may have causedthe Humming- birds to concentrateto an unusualextent in the irrigateddistricts. _TheLos Angelesrainfall recordsshow that 1923 was alsodeficient in moisture,though a cool springand heavy late rains along the foothillskept the wild flowersblooming well into the summer. in 1926the precipitation wassomewhat above normal, and in 1922 still more so. It will be observed that the net results in the various yearswere morenearly uniform than the originalnumber of nests. Incidentally, I find no evidencein support of the belief that a Hummingbirdprefers to returnand build again on the siteof its previousnest. The totalsin the abovetable showthe numberof youngfledged to be.almost exactly one-third of the numberof eggslaid. While someof thosewhose eggs were destroyedundoubtedly built new nests,relatively few were found which had been started after the main nestingperiod in April or May. Unlessresults are more favorable in other localities, the small increase indicates that the Hummingbirdmust enjoy a longlife for a creatureof its size. As an offsetto the destructionby teamsor implements,which usually occurredat an early stage,a numberof the nestswere tied up to prevent their occupantsfrom being spilled out by reasonof the faulty constructionpreviously alluded to. Lackingthis assistance, the lossesunder that heading would certainly have been much larger. It is notablethat in only oneinstance were natural enemies clearlyresponsible for loss. Althoughthis nestwas on a smalllimb about four feet from the groundand the youngwere killed during the daytime, strongcircumstantial evidence in the shapeof foot- printspointed to the SpottedSkunk as the culprit. Mr. Dawson's 'Birds of California' contains the information that Allen's Hummingbird, amongothers, rears two broodseach year, while the Costa'sand CalliopeHummingbirds have but one. Without desiringto discredit these statements,which may be basedon the mostcareful investigation, it is hard to seewhy the moreprolific species would not gain in numbersat the expenseof the others,so nearly identicalin structureand habitsand subject to the same hazards. 314 Woo,s,Hummingbgrds ofCalifornia. [JUlyIAuk

None of the other speciesshare the preferenceof Costa's Hummingbirdfor arid regions,nor breedso generallyin the Lower Sonoranzone, to which the Costa'sis largely confined. Anna's Hummingbird, according to Dr. Grinnell (Distributional List of the Birds of California),breeds almost entirely in the Upper Sonoranzone. Its breedingrange lies wholly within the State of Californiaand northernLower California,while its migration is only partial and it is a commonresident of all the moredensely populatedsections of the State, aboundingin city parks and gardens. How fitting it would have been,then, if M. Lesson,in- steadof attachingto this speciesfor all time the nameof a member of the Europeannobility who probably never saw a live Humming- bird, had namedit for the great provinceof whichit is socharacter- isticallya partI Perhapseven yet this splendidspecies might by commonconsent become officially known as the California Hum- ming bird; if so, the writer respectfullyoffers this suggestion to publishersof future handbooksand check-lists. The Black-chinnedHummingbird is typical of the foothills and canyonsof the lesshumid portionsof the West, and is said to be more dependentupon the presenceof water than any other species. That it can on occasiondispense with this desirable commoditywas madeevident to the writer upon meetingwith this speciesin an Upper Sonorancanyon in southernArizona at a time when,owing to unprecedenteddrought, the streamhad long since run dry. Aside from a very few scatteredmescals, there was an entire lack of flowers,in lieu of which the Hummingbirdswere systematicallyprobing the clustersof leavesat the ends of the live oak twigs. The Broad-tailed Hummingbird, preSminently a mountain dweller,is a comparativelyrecent addition to the recordedavifauna of California,since the limited portionof the State in which it occurs is one of the least frequentedregions in the United States. It seemsreasonable to supposethat it may eventuallybe found as a migrant, at least, farther south in the mountainsof easternSan BernardinoCounty. The appearanceof the Broad-tailed Hummingbird is not especiallydistinctive in any way. The color of the gorget,aside from its somewhatinferior brilliancy, is very similar to that of Vol.1927 XLIV| ] WOODS,Hummingbirds ofCalifornia. 315

Anna's Hummingbird, though showingat some anglesa more purplishcast. A convenientrecognition mark of themale is the rufousedging of certainof the tail feathers,in conjunctionwith the solidgreen color of the back and uppertail-coverts. It may safelybe said that the Broad-tailedHummingbird is muchmore readily identifiedby ear than by eye. The loud metallic noise producedby the flight of the maleis an agreeable,almost musical sound,clearer in tone than that made by the Rufous, Allen's or Black-chinnedHummingbirds, while the notesof the femaleseem moreliquid than thoseof other species.A rather faint, muffled staccatonote is uttered twice in quick successionat the lowest pointof its verticallydiving nuptial flight. Todigress slightly from the subject athand, the rather unusual distributionof the large genusSelasphorus is worthy of notice. In addition to the three wide-rangingNorth Americanspecies, the genuscontains five speciesof small size,all of whichare confined to the highlandsof CostaRica and westernPanama. Since noneof thenorthern species migrate farther south than Guatemala, thereis no contactwhatever between the two groups.

•VIENTALITY. Few animals have aroused such widely divergent opinions regarding their mental capacity as have the Hummingbirds. By most naturalists, probably, they have been credited with a high degree of intelligence. It would seem, however, that many of the instancescited as •v/denee of reasoningability, usually in connect/onw/th the constructionof their nests,might as readily be assignedto accidentor instinct. On the otherhand, I believethat few observerswill concurin the judgmentof the late W. H. Hudson, who devoted a chapter of 'The Naturalist in La Plata' to a discussionof the characteristicsof the Humming- birds as a group, in the courseof which, while greatly admiring their physicalendowments, he classesthem with the insectsas to intelligence;in fact, in the caseof the bumblebees,even to the advantage of the latter. Hummingbirds, says Mr. Hudson, "possessthe avlan body but do not rank mentally with birds. The pleasureone takes in their beauty soonevaporates, and is succeededby no fresh interest, so monotonousand mechanical 316 Woo,s,Hummingbirds ofCalifornia. [July[Auk are all their actions;and we accordinglyfind that thosewho are most familiar with them from personalobservation have very little to say about them. A scoreof humming-birdsof as many distinct species,are lessto the student of habits than one little brown-plumagedbird haunting his garden or the rush-bedof a neighboringstream..." With all due respectto Mr. Hudson'seminence as a naturalist, one cannot but feel that his attitude was unusual--certainly'far different from that of John Gould, author of the 'Monograph of the Trochilidae,'who says: "That our enthusiasmand excite- ment with regardto mostthings become lessened, if not deadened, by time, particularly when we have acquiredwhat we vainly considera completeknowledge of the subject,is, I fear, too often the case with most of us; not so, however, I believe, with those whotake up the studyof the family of HummingBirds. Certainly I can affirm that suchis not the casewith myself;for the pleasure which I experienceon seeinga Humming Bird is as great at the presentmoment as whenI first sawone." Many of Mr. Hudson's argumentsdo not seem convincing. He says: "It hasfrequently been remarked that humming-birdsare more like insectsthan birds in disposition.... Their aimless attacks on other speciesapproaching or passingnear them, even on large birds like hawks and pigeons,is a habit they have in commonwith many solitary wood-boringbees. They also, like dragon-fliesand other insects,attack each other when they come togetherwhile feeding.... Again, like insects,they are un- disturbed at the presenceof man while feeding, or even when engagedin buildingand incubation;and like varioussolitary bees, wasps, etc., they frequently come closeto a personwalking or standing,to hover suspendedin the air within a few inchesof his face; and if then struck at they often, insect-like,return to circle round his head. All other birds, even those which display the least versatility, and in districts where man is seldomseen, show as much caution•s curiosityin his presence;they recognizein the upright unfamiliarform a living beingand a possibleenemy." The similarity of the Hummingbird'shabits to thoseof certain insectsunquestionably creates the impressionof an equalsimilarity in mental traits. It is quite possible,however, that thoughcertain Vol.1927 XLIV] , Wool)S,Hummingbirds ofCalifornia. 317

actionsare performedmechanically by insects,the same actions on the part of the Hummingbirdmay be entirely volitional. Consideringthe difficulty of drawing definite lines of demarcation betweenreason, instinct and reflex action even in the caseof one's own accustomedactivities, it would be rash to make dogmatic assertionsas to the psychologyof so distantlyrelated a creature as a Hummingbird;but it may be observedthat the habits which it is said to have in common with insects are also shared to a greater or less extent by some other birds and mammals, so it would seem fair to assume that its mental reactions in connection therewithwould most closely resemble those of the higheranimals to which it is related. The matter of its attacks on other birds has already been discussed. The Hummingbird'sindifference to the presenceof man, which as a matter of fact is by no meansso complete as wouldbe inferred, might be justifiedon the groundsof its quicknessof movementand its comparative freedom from molestation. It is true that it resemblesthe insectsin its apparentrecognition of possibleenemies rather through their movementthan by their form, but this applies to a certain extent to most birds and many mammals, whileon the otherhand, those who have attempted to photograph Hummingbirds under various conditions probably will have discoveredthat they are sometimesquite assuspicious of unfamiliar objects,whether living or inanimate,as are most other birds--one female even refusedto approachthe nest and feed her young while the camerawas standingabout three feet away. And as to curiosity,if that is to be regardedas an indicationof deficient mentality,naturalists must be assigneda very low positionon the scaleof intelligenceI To againquote Mr. Hudson: "Humming-birdsoften fly into openrooms, impelled apparently by a fearlesscuriosity, and may then be chasedabout until they drop exhaustedor are beaten downand caught,and as Gouldsays, 'if then taken into the hand, they almostimmediately feed on any sweet,or pump up any liquid that may be offeredto them, without betrayingeither fear or resentmentat the previous treatment.'" •Vir. Hudson then cites the similar behaviorof dragon-flies,and continues: "Only in beingsvery low in the scale of nature do we see the 318 woo,,s,Hummingbirds ofCalifornia. JulyAuk instinct of self-preservationin this extremely simple condition, unmixed with reason or feeling, and so transient in its effects. The sameinsensibility to dangeris seenwhen humming-birds are capturedand confinedin a room, and then, beforea day is over, they will flutter about their captor's face and even take nectar from his lips." In the comparisonof the behaviorof Hummingbirdsand dragon flies, the true test would appear to be, not in their actionswhen first caught, but when again approachedafter being released. tn such circumstancesan insect would doubtlessuse exactly the sameeffort to avoid recapturethat it had usedin the first place, modifiedonly by physicalexhaustion. The action of the Hum- mingbirdwould be quite different,according to Mr. Hudson'sown statement and many other accountsof the ease with which it may be tamed, a trait which it shareswith no lesssagacious a beast than the elephant,and which in itself would seemto imply a certaindegree of intelligence. Though compelledto admit that I have so far been able to detect no indicationof the Hummingbird'spossession of reasoning ability--an accomplishmentwhich, after all, is rarely enough displayedeven by the human race--and that it may be lacking in someof those finer emotionswhich make many of the birds seem so akin to mankind, neverthelessits actions and attitudes, its alert interestin its surroundings,its apparentlove of sportand its ability to recognizethose who befriendit, as attestedby many - writers, certainly furnish competentevidence of an acutely con- sciousintelligence. Suffice it to say, in conclusion,that the Hummingbird'sequipment--physical and mental--is sufficient to enableit to maintain its numberssuccessfully with an unusually small potential annum increase,.comparable in general only to that of certain birds and mammalsof many times its size. Azusa,California.