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    J. comp. Physiol. 89, 73--82 (1974)9 b y Springer-Verlag 1974

    D etection of Changes in Atm ospheric Pressureby the H om ing Pigeon o l u m b a l i v i a

    M e l v in L . K r e i t h e n a n d W i ll ia m T. K e e t o nDivision o f Biological Sciences, La ngm uir L abo ratory , Cornell Un iversity,

    I thaca , New York

    Received October 23, 1973

    Summary.Homing pigeons were tested for their ability to detect air pressurechanges in an otherwise constant environment chamber. Ten of 12 birds testeddid respond to the pressure changes. The 50% threshold of detection was 10 m mH2 0 or less, which is app rox im ately equiva lent to a change in altitude of 10 in orless. Perfo rm ance was bet ter in a ch am ber with artificial backg round noise than inan abnorm ally quiet chamber.

    I n t r o d u c t i o n

    T h e a b i l i t y t o d e t e c t c h a n g e s i n a t m o s p h e r i c p r e s su r e w o u l d b e u s e fu lt o a b i r d , b o t h w h e n f l y in g a n d w h e n o n t h e g r o u n d . ~ V he n t h e b i r di s f l y i n g , a p r e s s u r e d e t e c t o r c o u l d b e u s e d a s a n a l t i m e t e r. A l s o, if i tw e r e s e n s i t i v e e n o u g h , t h e r a t e o f c l i m b o r d e s c e n t c o u l d b e d e t e r m i n e df r o m p r e s s u r e i n f o r m a t i o n a l on e . M o r e o v e r , th e r e a r e p a t t e r n s o f a i rt u r b u l e n c e w h i c h , if d e t e c t e d , c o u l d p r o v i d e d i r e c t i o n a l c ue s . S u c hd i r e c ti o n a l in f o r m a t i o n c o u l d b e of u s e t o n o c t u r n a l m i g r a n t s w h e n t h e yf l y i n h e a v y c l o u d c o v e r.

    I t i s b e c o m i n g i n c r e a s i n g l y c l e a r t h a t m i g r a t i n g b i r d s a r e e x c e l l e n tm e t e o r o l o g i s ts . M i g r a t io n t a k e s p l a c e o n r e l a t i v e l y f e w n i g h t s o f e a c h

    s e a s o n a n d t h e s e n i g h t s a r e p r e d i c t a b l e f r o m s y n o p t i c w e a t h e r c o n d i ti o n s.I n p a r t i c u l a r , s p r i n g m i g r a t i o n t e n d s t o b e c o n c e n t r a t e d o n e v e n i n g so f s o u t h w i n d s , r is i n g t e m p e r a t u r e , a n d f a ll in g p r e s su r e , w h e r e a s f a llm i g ra ti oD i s m a x i m u m o n d a y s w i t h n o r t h w i n ds , f al li n g t e m p e r a t u r e ,a n d r i s in g p r e s su r e ( B a g g e tal. , 1 9 5 0; B r u d e r e r , 1 97 1 ; N i s b e t a n d D r u r y ,1 9 6 8 ; R i c h a r d s o n a n d t t a i g h t , 1 9 7 0 ; R i c h a r d s o n a n d G u n n , 1 9 7 1 ) .M u l l e r ( 19 72 ) f o u n d t h a t W h i t e - t h r o a t e d S p a r r o w sZonotrichia alb i-collis)k e p t i n o u t d o o r c a g e s s h o w e d i n c r e a s e d a c t i v i t y o n n i g h t s w h e ns p r i n g m i g r a t i o n w o u l d n o r m a l l y b e h e a v y . I n t h e s p r i n g , si g n i fi c a n tc o r r e l a t i o n s w e r e o b t a i n e d b e t w e e n a c t i v i t y a n d r i s i n g t e m p e r a t u r e ,s o u t h w i n d s , a n d a d e c r e a se in a t m o s p h e r i c p r e s s u r e g r e a t e r t h a n1 7.3 m m H ~ O . T h u s i t is a p p a r e n t t h a t m i g r a t i n g b i rd s g o a lo f t m o s tf r e q u e n t l y a n d i n g r e a t e r n u m b e r s o n e v e n i n g s w h e n t h e r e a r e f o l l o w i n gw i n d s a l o f t. T h e m e t a b o l i c c o s t o f lo n g d i s t a n c e f l ig h t i s h i g h , a n d b y

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    74 M. L. Kreithen and W. T. Keeton

    using the wind to the ir advantage , birds ma y be able to ext end the

    distance f l o~ on a given amo unt of fa t reserve .Although most par ameters of weather are corre la ted with one another,

    the barom eter is s t i ll an essent ial tool for the meteorologist ; presumably,barometr ic infor mati on could be of similar va lue to a bird in predic t inga nig ht s weath er conditions. Masher an d Stolt (1961), who ke pt ab u n t i n g Em beriza hortulana)in an envi ro nment a l chamber in whichonly a ir pressure was a l lowed to vary natura l ly, repor ted a negat ivecorre la t ion between the level of ac t ivi ty and changes in a tmospher icpressure . Lehner and Dennis (1971) have repor ted tha t mallard duckscan be t ra ined to peck the appropr ia te keys of a test appara tus whenthe re is a pressur e change of :[: 2 psi, 1 psi, an d ~: 0.4 psi over aninterval of approximate ly 2 minutes . These pressures correspond toa l t i tude changes of approximate ly 1200 meters , 600 meters , and 240meters.

    The purpose of the present s tud y is to de termin e if the h oming pigeoncan detect smM1 changes in atmospheric pressure. In particular, theexper iments concentra te on the kinds of pressure changes tha t wouldbe experienced by a bird in free f light.

    e t h o d s

    The basic materials for the experiments were an airt ight chamber, a controlledsource of air, and equipment to monitor the heart rate.

    The sealed pressure chamber (obtained from the U.S. Navy), which was designedfor withstanding pressures much greater than any we used, had cast aluminiumwalls 2.3 cm thick, plus external ribs 1 cm thick. I ts inte rnal volume was 40 liters,and the floor dimensions were 44.5 by 30 cm. Air and vacuum were supplied throughsound isolation mufflers made of 6-inch lengths of 2-inch diameter galvanizedpipe, packed with aquarium floss. For respiration, there was a constant flowof 5 liters /minute of fresh air th rough the chamber. Changes in chamber pressure

    were programmed by a system of solenoid-operated needle valves which controlledthe rates of air flow into and out of the chamber . Because the compressed airsupply and the vacuum source operated at pressures very much greater than thechamber pressure, all changes in chamber pressure were linea r with time.

    Instant aneous heart rate was monitored with a Grass Ins tru ment Co. model7P4 tachograph. The output of the taehograph is a linear voltage proportional toheart rate, measured on a beat-to-beat basis. A permanent record of chamberpressure, EKG, and hear t rate was obta ined with a Sanborn model 350 chartrecorder.

    The basic method was simply to change the pressure over a 5 sec interval,hold the new pressure for another 5 see, and th en del iver a mild electric shock tothe pigeon. After a few such presentations, a condit ioned response develops andthe heart r ate increases when the pressure changes. Fig. 1 shows the cardiac response.Each experiment consisted of 50 trims of pressure change followed by shock.

    In the chamber, each bird was gently restrained in a leather body harnessand placed in a sculptured foam rubber cushion with the body axis horizontal.The head was free to move in any direction. Two EKG surface electrodes were

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    D e t e c t i o n o f C h a n g e s i n A t m o s p h e r i c P r e s s u r e b y t h e H o m i n g P i g e on s 7 5

    A. Experimental

    a Time

    B. Control

    :~ 2

    ~ o o t _ _ ~ j = = t = = = t , - - ~ t = = = l t r---~ f ~ - - ~ t - - I ~ = =

    Time ~ [:::::::3 ~ Stimulus presented

    [ Beginning of new trial

    F ig . 1 . Trac in g s o f ac tu a l ca rd iac r a t e s d u r in g an ex p er im en t . U p p e r t r ace i s 1 0co n secu t iv e f r am es a t =~ 2 0 m m H 2 0 p ressu re ch an g e . H a tch ed a rea in d ica t esp ressu re ch an g e . S h o ck fo l lo w s a t t h e en d o f th e p ressu re ch an g e . T h e ch a r t i ss t o p p e d a t t h e a r r o w, a n d r e s t a r t e d a t r a n d o m t i m e i n t e r v al s . L o w e r t r ac e i s f r o m

    a c o n t r o l tr i a l u s in g t h e s a m e b i r d . I n t h e u p p e r t r a c e , f r a m e n u m b e r 7 i s t h e o n l yo n e th a t d o es n o t m ee t c r i t e r io n fo r a ca rd iac r e sp o n se . In th e co n t ro l t r ace , f r am en u m b e r 8 h a s a n a c c e l e ra t i o n d u r i n g t h e s t i m u l u s t i m e i n te r v a l , b u t t h e m a g n i t u d e

    o f th e acce le ra t io n i s t o o sm al l t o b e co u n ted as a r e sp o n se

    a t t a c h e d , o n e a t t h e b a s e o f t h e ne c k , d o r sa l s u rf a ce , a n d t h e o t h e r u n d e r t h e r i g h tw in g , j u s t p o s t e r io r t o th e b ase o f t h e h u m eru s . S h o ck e l ec t rod es w ere tw o s i lv e rw i re s i m p l a n t e d u n d e r t h e s k i n o f t h e b r e a s t , o n e o n e a c h s id e o f t h e s t e r n u m . T h esh o ck , w h e n d e l iv e red , w as 1 m a fo r 3 5 0 m sec f ro m a 6 0 H z A .C . co n s tan t - cu r r en tsource .

    T h e c o n t r o l f o r e x t r a n e o u s c u e s w a s t o r u n t h e e x p e r i m e n t i n t h e u s u a l w a y,b u t w i t h a v a l v e o p e n e d t o t h e o u t s i d e o f t h e c h a m b e r s o t h a t n o p r e s s u r e c o u l daccu m u la te in s id e . T h i s p ro ced u re a l lo w ed ev e ry th in g su ch as a i r - f lo w ra t e s ,r e l ay n o ises , v a lv e so u n d s , e t c . t o p ro ceed in t ac t , b u t d id n o t p e rm i t t h e a i r p ressu reto v a ry.

    T h e c a r d i a c a c c e l e r a t i o n r e s p o n s e w a s m e a s u r e d b y c o m p a r i n g t h e h e a r t r a t eb e f or e t h e p r e s s ur e c h a n g e w i t h t h e h e a r t r a t e d u r i n g o r i m m e d i a t e l y a f t e r t h e p r e s-su re ch an g e . F o r each s t im u lu s p resen ta t io n , a b ase l in e w as e s t ab l i sh ed b y d e -t e r m i n i n g t h e p e a k h e a r t r a t e i n t h e 5 - s e c o n d i n t e r v a l p r e c e e d i n g t h e p r e s s u r ech an g e . F o r a r e sp o n se to b e co u n ted , t h e h e a r t r a t e d u r in g th e 1 0 - seco n d p ressu re -c h a n g e i n t e r v a l m u s t h a v e e x c ee d e d t h e b a s e l i n e r a t e b y a t l e a s t 12 b e a t s p e r m i n u t e .Mo s t ca rd iac r e sp o n ses eas ily ex ceed ed th i s m i n im u m req u i r em en t . Ty p ica l b ase l in eh e a r t r a t e s w e r e a p p r o x i m a t e l y 1 4 0 b e a t s p e r m i n u t e , a n d a c c e l e r a t i o n s o f 3 0 t o6 0 b ea t s p e r m in u te w ere co m m o n see F ig . 1) .

    T h e p a t t e r n s a n d m a g n i t u d e s o f t h e r e s p o n s e s w e r e i n c o m p l e t e a g r e e m e n tw i th th e ex ten s iv e s tu d ies b y C o h en an d h i s co -w o rk er s o f t h e co n d i t io n ed ca rd iacresp o n se o f t h e p ig eo n C o h en an d M acD o n a ld , 1 97 1) .

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    76 M. L. Kreithe n and W. T. Kee ton

    8 O

    7 C

    ~ 5 3

    ~ 4 C

    g o

    1

    B i r d : 5 2 6

    .

    I ~ t t t t w l v f I I i- I 0 0 0 I 0 0 2 0 0 3 0 0 4 0 0

    P r e s s u r e r a m H 2 0 )

    Fig. 2. Responses to atm osp her ic pressure changes. Solid circles are perc ent cardiac

    responses to 50 trials at the indicated pressure. Solid square is a control exp erim ent(50 trials). Op en circles indicate the train ing sessions o~ 50 trims e ach ; arrowsindicate their sequence. Pressures not connected by arrows were presented in

    mixed order

    es u l t s

    T h e r e s u l t s c l e a r l y s h o w t h a t h o m i n g p i g e o n s c a n d e t e c t s m a l l di f-f e r e n t i a l c h a n g e s i n a i r p r e s s u r e . Tw e l v e p i g e o n s w e r e t e s t e d a t i n i t i a lp r e s su r e s d i ff er in g f r o m a t m o s p h e r i c b y 1 0 0- 4 00 m m H 2 0 . Te n o f t h eb i r d s e a s i l y m e t o u r c r i t e r i a f o r r e g u l a r r e s p o n s e . Tw o b i r d s d i d n o tr e s p o n d s a t is f a c to r i ly a f t e r 5 0 tr i a ls a n d w e r e r e m o v e d f r o m f u r t h e re x p e r i m e n t s ( r e f r a c t o r y s u b j e c t s h a v e o f t e n b e e n r e p o r t e d i n c a r d i a cc o n d i t i o n i n g e x p e r i m e n t s ; Tu g e , S m i a a n d K o g a , 1 9 5 7 ) .

    F i g . 2 s h o w s t h e r e s p o n s e p a t t e r n o f o n e o f t h e b i r d s w h o s e p r e s s u r es e n s i t i v i t y w a s e x a m i n e d i n d e t a il . T h e r e i s a c h a r a c te r i s t i c d i p i n t h en u m b e r o f r e s p o n s e s a t l o w p r e s s u r e d i ff e r en t ia l s . T h e b a c k g r o u n dl e v el is th e v a l u e f o r t h e c o n t r o l t e s t (0 m m H ~ O c h a n g e ) ; t h i s v a l u er a n g e d f r o m 8 t o 1 6 f o r t h e v a r io u s b i r d s t e s t e d .

    Ramp Tests To d e t e r m i n e t h e p a t t e r n o f s e n s i t i v i t y t o p r e s s u r ev a r i a t i o n s b e t w e e n 0 a n d 2 0 m m H 2 0 , 4 c o n d i ti o n e d b i r d s w e r e s u b j e c t e dt o a s e r ie s o f l i n e ar p r e s s u r e in c r e as e s a t t h e r a t e o f 2 m m H 2 0 p e r s e c o n df o r 1 0 s e e. T h i s i s s im i l a r t o t h e t e s t p r o c e d u r e u s e d b y D r e s s l e r ( 18 93 ),w h o f o u n d t h e h u m a n t h r e s h o ld f o r p re s s u re c h a n g e to b e a b o u t 4 0 m mH 2 0 . T h e p r e s su r e a t w h i c h t h e h e a r t r a t e b e g a n t o r is e w a s p l o t te do n a h i s t o g r a m ( F ig . 3 ). T h e m e d i a n v a l u e o f p r e s s u r e re s p o n s e s r a n g e df r o m 6 .4 t o 1 0.8 m m H ~ O f o r p o s i ti v e c h a n g e s in p r e s s u re , a n d f r o m 7 .6 t o8 .8 m m H 2 0 f o r n e g a t i v e c h a n g e s . P i g e o n ~ o . 110 3 g a v e o n l y 2 r e s p o n s e st o 5 0 n e g a t i v e p r e s s u r e r a m p s , a n d w a s th e r e f o r ~ n o t c o n s i d er e d t o b es e n s it iv e t o p r e s su r e c h a ng e s b e tw e e n 0 a n d - - 2 0 m m H 2 0 .

    Threshold Values T h e r e a p p e a r s t o b e n o s h a r p t h r e s h o l d o f A - p r e s -s u r e s e n s i t i v i t y. A s t h e p r e s s u r e c h a n g e a p p r o a c h e d z e r o , t h e p e r c e n t a g eo f re s p o n s e s d e c r e a s e d p r o p o r t i o n a t e l y.

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    Detection of Changes in Atmospheric Pressure by the Homing Pigeons 77

    + P ressure rnrnH 20) - P r e s s u re m m H 2 0 )

    |. . . . j 3 26 0 . . .

    f i

    . I . I , I . I . , , , , , , l . . l . i ,f . . . . . .

    l

    , . I f . . o , 3 ~ 6 o i . . . I , . , I . .

    9 , ,~ . . . . . . . . . . f , ~ , =

    I I Noesponse9 : . . I l l I l , I i 0 3

    ~ig. 3. Ramp tests. Histogram of responses by four birds to linear pressure changesof ~= 20 mm H20 in 10 sec (see text for explanation). Arrows indicate median values.The abcissa shows the pressure-change values a]ong the ramp from 0 to 20 mm H~O.

    Each data point indicates the pressure at which response began in one trial

    There was some evidence of responses to pressure changes down toas little as 1 mm H20. Fig. 4 shows one att em pt to find the thresh old ofsensiti vity for bird No. 3560. Exp erim enta l trials were presented inmixed sequence, without removing the bird from the chamber, for ama ra th on session of 16 hours. Responses to a change of + 1 mm H~Owere higher than control trials run concurrently. An estimate of the 50

    threshold point, a measure commo nly used in psychophysics, is about6 mm H20. This agrees well with th e me dian v alue of the r amp test,which was 6.4 mm H~O for this bird. Also on Fig. 4 are data from earlierexperiments (closed circles).

    T h e E ] / e c t o ] A c o u s t i c N o i seThe performance of the birds wasinfluenced by the ambient noise level in the chamber. The usual effectof reducing the background noise was to decrease the percentage ofresponses to a given pressure change. Fig. 5 shows the results of ninepaired experiments where 50 trials were presented with no noise addedto the chamber and 50 trials were presented with continuous noiseadded through a 4-inch diameter loudspeaker driven by a GeneralRadio random-noise generator. The pressure stimulus was presentedin alterna ting blocks of 10 trials, first with ad ded noise, and th en wi tho utnoise.

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    78 M L K r e it h e n a n d W T K e e t o n

    C

    B i r d : 3 5 6 0

    5 0 ~ e..... ~"

    ~) A - V a l u e s o b t d i n e din~: 3C j one 16 hou r sess iono ~ ,"~ , / 9 - Va l u es f ro m o l d e r

    n ~ 2 0 d a t a

    10

    I , I , 1 I t I t 1 .....0 ' 4 8 1 2 1 6 2 0 2 4 2 B 3 2

    /% P r e s s u r e ( m m H 2 0 )

    Fig . 4 . Se ns i t iv i ty p lo t fo r b i rd 1~o. 3560 . R esponses to pos i t ive p ressu re changesp re s e n t e d i n mi x e d s e q u e n c e . Ea c h d a t a p o i n t i s p e rc e n t r e s p o n s e t o 5 0 t r i a l s

    s e e t e x t fo r e x p l a n a t i o n )

    8O

    6 0 -

    o 4 0 -

    2 0 -

    F - I N o i s e a d d e d

    N o n o i s e

    - 4 0 + 2 0 R - 5 0 - 2 0

    3 2 6 0

    " r +5 0 - 4 0 + 3 0 +5 0 - ,, -- -Test P res sure_ _ 1 1 I m m H 2 0 )

    v. '5 1 89 3 5 "S 0 4 - - B i rd Nu mb er

    F i g . 5 . P a i r e d e x p e r i me n t s s h o w i n g t h e e f fe c ts o f a m b i e n t n o i s e l e v e ls o n d e t e c t i o no f p r e s s u re c h a n g e s . Te s t p r e s s u re s a r e b e l o w e a c h h i s t o g ra m. R i n d i c a t e s a l i n e a r

    p re s s u re r a m p o f t h e i n d i c a t e d p re s s u re me a s u re d o v e r 1 0 s e e

    I n 8 o f t h e 9 e x p e r i m e n t s , t h e r e w a s a h i g h e r p e r c e n t a g e o f r e s p o n s e sw i t h n o is e a d d e d t o t h e c h a m b e r t h a n w i t h o u t . F i g . 6 s h o w s th e s p e c t r a ld i s t r i b u t i o n o f s o u n d p r e s s u r e l e v e ls w i t h i n t h e c h a m b e r . I t c a n b es e e n t h a t t h e t h i c k w a l l s o f t h e c h a m b e r e f f e c t i v e l y f i l te r e d o u t s i d es o u r c e s o f n o is e . I t i s u n l i k e l y t h a t t h e b i r d i s e v e r i n a n a t u r a l e n v i r o n -m e n t a s q u i e t a s t h e i n s i d e o f t h e c h a m b e r w i t h o u t n o i s e a d d e d .

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    Detec tion of Changes in Atmospheric Pressure b y the Hom ing Pigeons 79

    7(;

    6C

    ~ c

    r

    ROOm A- '~ A~ A

    C h o e / / ~W it ho ut n oi se 0 ~ o . . . . . z~

    ~ ~ I O ~ 0 ~ 0 ~ 0

    0 dB =.0002 dynes/crn 2

    [ I I . . . . I I | I

    51.5 6 5 125 250 500 I000 2000 400 0Frequency (Hz)

    Fig. 6. Spe ctral distribution of sound pressure levels inside the cham ber bothwith and without added noise. Triangles show the ambient noise in the room

    for reference

    D i s c u s s i o n

    T h e h o m i n g p i g e on is a p p a r e n t l y a b l e t o d e t e c t a t m o s p h e r i c p r e ss u r ec h a ng e s o n t h e o r d e r o f l0 m m H 2 0 o r lo w e r w h e n t h e s e a r e p r e se n t e do v e r a 5 s e e i n t e r v a l . T h e 5 - se c in t e r v a l w a s a n a r b i t r a r y, t h o u g h b i o lo g i-c a l l y r e a s o n a b l e , e x p e r i m e n t a l c h o ic e ; i t is p r o b a b l y s a fe to e x t e n d t h e s ef i n d in g s t o 3 0 s e e o r m o r e . G i v e n t h i s s e n s i t iv i t y, i t i s a p p r o p r i a t e t od i sc u s s th e p o t e n t i a l u s e o f t h i s i n f o r m a t i o n , a n d t o s u g g e s t f u r t h e re x p e r i m e n t s .

    Control o/AltitudeR a d a r s t ud i es r e p o r t t h e a l ti tu d e s o f m i g r a t i n g

    b i r d s t o b e m a i n t a i n e d w i t h i n =j= 2 0 m e t e r s , e v e n w h e n c l ou d s o b s c u r et h e g r o u n d , h o r i z o n , a n d s k y G r i f f in , 19 6 9, 1 97 2). S i n c e a 10 m m H 2 0A - p r e s s u r e t h r e s h o l d i s e q u i v a l e n t t o a p p r o x i m a t e l y 1 0 m o f a l t i t u d ec h a n g e , i t is f e a s ib l e t h a t a b i r d c o u l d m a i n t a i n t h e o b s e r v e d a l t i t u d el i m i t s u s i n g a p r e s s u r e s e n s e a l o n e .

    T h o u g h i t i s c l ea r f r o m t h i s s t u d y t h a t h o m i n g p i ge o n s c a n d e t e ctb o t h p o s i t i v e a n d n e g a t i v e p r e s s u r e c h a n g es , w h a t i s n o t y e t k n o w n i sw h e t h e r t h e y c a n d i s c r i m i n a t e b e t w e e n i n c r e as i n g a n d d e c r e a s i n g p r e s -s u r e c h a n g e s. F o r a p h y s i o l o g ic a l a l t i m e t e r t o f u n c t i o n p r o p e r l y, t h i sa b i l i t y w o u l d b e u s e f u l b u t n o t a b s o l u t e l y e ss e n ti a l.

    Locating Thermal UpdraftsG l i d e r p i l o t s u s e a v e r y s e n s i t i v e p r e s s u r ei n s t r u m e n t t h e v a r i o m e t e r ) t o d e t e c t t h e sm a l l r a t e s o f a l t i t u d e c h a n g ea s s o c i a t e d w i t h t h e r m a l u p d r a f t s . S o a r i n g b i rd s w i t h a s u f f i ci e n t lys e n s i t iv e p r e s s u r e d e t e c t o r c o u l d p r e s u m a b l y u s e p r e s s u r e i n f o r m a t i o n

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    Detection of Changes in Atmospheric Pressure by the Homing Pigeons 81

    appropriate way, but it is still not known whether pressure or some

    other correlated variable is the cause of the increase in activity (Bagge t a l . 1950; Masher and Stolt, 1961; Muller, 1972).

    N o t e s o n M e c h a n i s m s . There is curren tly no evidence indicatin g wherethe pressure receptor might be. However, the interaction between whitenoise in the chamber and responses to pressure suggests that the earmay play some role.

    The modification of ambient noise is of course a possible mechanismin it, ll . The bird norma lly flies in an envi ronment filled with the soundsof wingbeats, rushing air, and the vocalizations of other birds. A shift

    in auditory sensitivity associated with changes in air pressure could beused as a means of detec ting changes in pressure. Beecher (1951, 1954)has reported the presence in birds of cavernous tissue capable of comple-tely sealing off the external ear when inflated with blood. The tissue canapparently seal off the external ear without pressing on the tympanum(Beecher, pers. comm.). Such a sealed, and presumably temperature-regulated, air volume could provide the necessary reference cell for de-tecting absolute pressure.

    There are, of course, other ways that pressure could be detected bythe ears. For example, stretch receptors in the tympanum could providethe necess ary signals. The func tion of Vitalli s o rgan is as yet unkno wn,but it may be related to detecting static pressures in the endolymph(Griffin, 1969). The possib ility tha t the ears are the dete ctio n sites couldbe tested by using tubes fitted to the external ear, which would allowthe ears and the rest of the body to be tested separately.

    There are also other potential sources of pressure-detecting mecha-nisms. Birds have many air-filled spaces any one of which could be apotential pressure sensor. Thus stretch receptors in the walls of an airsac could serve as an isothermal barometer. Alternatively, sensory

    hairs could be used to detect air flow in and out of hollow bones in amanner analogous to the detection of fluid flow in the semi-circularcanals (Lowenstein and Sand, 1940).

    In any event, the findings reported here provide a foundation onwhich future study of the pressure capabilities of birds may be built.

    We thank Drs. D. R. Griffin, K. Adler, and J. Hatch for reading and criticizingan early draft of this paper. This work was supported by an NSF Graduate Fellow-ship to M. Kreithen, a grant from the Conlell Office of Sponsored Research, andNSF Research Grants GB 13046X and GB 35199X to W. T. Keeton.

    e f e r e n c e s

    Bagg, A. ~L, Gunn, W. W. H., Miller, D. S., Nichols, J.T., Smith, W., Wolfarth,F. P. : Barometric pressure patterns and spring bird migration. Wilson Bull. 62,5-19 (1950)

    6 J. comp. Physiol. Vol. 89

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    82 M . L . K r e i t h e n a n d W . T. K e e t o n

    B e e c h e r, W . J . : A p o s s i b le n a v i g a t i o n s e n s e in t h e e a r o f b i rd s . A m e r. Mi d l a n d

    Na tu ra l i s t 46 , 367-384 (1951)Beecher, W . J . : On co r io l is fo rce and b i rd nav iga t ion . Sc i . M on th ly 79 , 27 -31 (1954)B ro u n , M. : H a w k s A l o f t, 22 2 p . N e w Y o rk : D o d d -Me a d 1 9 49B ru d e re r, B . : R a d a rb e o b a c h t u n g e n f ib e r d e n F r i ih l i n g s z u g im S e h w e i z e r is c h e n

    Mit te l land. Orni thol . Beob. 68 , 89-158 (1971)C o h e n , D . H . , Ma c D o n a l d , R . L . : S o me v a r i a b l e s a f f e c t in g o r i e n t i n g a n d c o n d i -

    t ion ed he ar t ra te responses in the p igeon . J . comp . phys io l . Psych o l . 74 , 122-133(1971)

    Cri tchfie ld , I -I . J . : G ene ral c l im atolo gy , 2nd ed . , 420 p . En glew oo d Cl i ffs, N. J . :P re n t i c e H a l l 1 9 6 6

    D re s s i er, F. B . : O n t h e p re s s u re s en s e o f t h e e a r a n d f a c i a l v is i o n . A m e r. J .Psychol . 5 , 344-350 (1893)

    G r i ff in , D . 1 ~ . : Th e p h y s i o l o g y a n d g e o p h y s i c s o f b i rd n a v i g a t i o n . Q u a r t . l ~ ev.Biol . 44 , 255-27 6 (1969)

    Gr i ff in , D. 1~ .: No c tu rn a l b i rd m ig ra t io n in opaq ue c louds . In : Gal te r, S . , Sehm id t -Ko en ig , K . , J aco bs , G . , Be l lv i l le , 1~ ., eds . , An im al O r ien ta t ion an d Na v iga t ion ,A S y mp o s i u m. N A S A S P 2 62 . W a s h i n g t o n , D . C .: U . S . G o v t . P r i n t i n g O ff ic e1972

    Hass le r, S . S . , G raber, 1~ . 1~ ., Be l l rose , F. C . : Fa l l m ig ra t ion and wea ther, a ra da rs tudy . W i l son Bu l l. 75 , 56 -77 (1963)

    Le h n e r, P. N . , D e n n i s , D . S . : P r e l i m i n a ry r e s e a rc h o n t h e a b i l i t y o f d u c k s t o d i s c r i-m ina te a tmo sphe r ic p ressu re changes . An n . N. Y. Aca d . Sc i . 188, 98 -109 (1971)

    Lo w e n s t e i n , O . , S a n d , A . : Th e i n d i v i d u a l a n d i n t e g ra t e d a c t i v i t y o f t h e s e mi c i r-

    cu la r cana l s o f the e lasm obran ch labyr in th . J . Phy s io l . (Load . ) 99 , 89 -101 (1940)M a s h e r, J . W . , S t o l t, B . : L u f t t r y c k e t s i n v e r k a n p a o r t o la n s p a r v e n sEmberizahortulana. L .)a k t i v i t e t u n d e r v a r f l y t t n i n g s p e r i o d e d . Va r F a g e l v a r l d 2 0, 9 7 -111(1961)

    M u l le r , E . E . : E f f e ct s o f w e a t h e r o n t h e n i g h t t i m e a c t i v i t y o f W h i t e - t h r o a ~ dSparrow s . M as te rs Thes i s , Corne l l Un iver s i ty (1972)

    N i s b e t , I . C . T. : A t m o s p h e r i c tu rb u l e n c e i n b i rd f l ig h t . B r i t . B i rd s 4 8, 5 5 7 -5 9 9(1955)

    N i s b e t , I . C . T. , D rn ry, W . H . , J r. : S h o r t te rm e f f ec t s o f w e a t h e r o n b i rd mi g ra t i o n :a f i e ld s tu dy us ing mu l t iva r ia te s t a t i s t i cs . An . Beh av. 16 , 496-530 (1968)

    R i c h a r d s o n , W . J . , G u n n , W . W. H . : R a d a r o b s e r v a ti o n s o f b i r d m o v e m e n t s i ne a s t - c e ri t ra l A l b e r t a . C a n . Wi l d l if e S e rv ic e R e p o r t S e r ie s N u mb e r 1 4 : 3 5 -6 8(1971)

    R i c h a rd s o n , W . J . , t t a i g h t , M . E . : M i g ra t io n d e p a r t u re s f ro m s t a r l in g ro o s t s.Canad. J . Zool . 48 , 31-39 (1970)

    Tuge , H . , Sh im a, I . , Ko ga , K. : Defens ive cond i t ione d re f lexes in p igeons . Phy s io l . J .U.S .S .R . (Seehenov) 48 , 766-776 (1957)

    M e l v in L . K r e i th e n a n d W i l li a m T. K e e t o nDiv i s ion o f B io log ica l Sc iencesL a n g m u i r L a b o r a t o r y, C o r n e ll U n i v e r s i tyI t h a c a , N e w Y o r k 1 48 50 , U S A