peregrine falcon recovery along the west central coast ...

J. h p h k .31(1):1-6 Q 1997 The Raptor Rcscarch Foundarion. Inc.

PEREGRINE FALCON RECOVERY ALONG THE WEST CENTRAL COAST O F THE BAJA W F O R N I A PENINSULA, M E X C O ARAD^^ CASTELLANOS C s n h h Invahgoaast Bidogruu del iV-te. S.C. Diu De B i d Trnaba. Apdo. Pas6 128. Lo P e B.C S . .Um.w

FERNANDO JARAM ILLO m 7 ConnJlom, SC. A+.

FEDERICO SUAS,

Pat. 1887. Ciurnnv-

iMm, Mitito

ALFREDOORTEGA-RUBIO AND CERAFINA ARCUELLES

Csntm de InucrtigaaOM B¿~~¡&car áel i V m t e , S. C . Diu & BwL T m r s t . , Apdo. Par6 128.

h Paz, B.CS. ~ M m w

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Amxxr.-The c c n d WUL cout of the Baja Cdifornia peninruL was an important Peregrine Falcon ( F h pnagrinur) brreding a r a supponing a popularion of abour 13 b r e e d i n ~pain. ThU popularion dcdined d r a s o d y during rhe 1960s and early 1970s We conducvd field survcy~and compiIed dan on n&g Percgrinepain fmm 1980.44 to addresr rhe currmt smau of the Baja p o p u l i o n . We found 10 p a i n naring in the M indicaring rhe Perrgrine popuiation has rccovered in thc arca since the l a u 1970s Due to increavd humui acfity in the arca. propcr managemenc is nceded to provide suitable naring s i c s and to minimize human dinirbances during the nsting -n. KN WORDS: Pmgrim F d a m m c m q s l a N Baja

Cali/mnia; falco peregriniis.

R c c u p a i ó n del halcón peregrino en la cosa centro ocadmral de la pcnisula de Baja Catifo-

,Wico.

~ . M E N cosu . - Lcenvo ~ ocodcnul de la península de Bija.Wioriiia. Iw, Jdo un k c a ímponuiu de reproducción dd halcÓn perelpuio ( F h pngfima).manteniendo alrededor dc i S tenimrios & anidaaón. E s a pobbaón dcdinó drhtiarmn~~ mm los d o s 1960s e inicios dc IOE1970s. Nosoma rr?immosaPidios endcampoy~osduaabnhplrrjyuiiduils&~osmm 1980y 1994par;rdrtermirur nisairi0nvauLEnconolmadierplrrjy&&01~dorndárraNm~~ q i w b . ~ 0 1 ~ ~ ~ r m i p m n d o d a d c ~ e 5 d c b r ~ 1 9 7 0 s . k r a c ~ h u m v u r &accimdorndLn.l~~~aanmvnauzyu>rnoopMnuudda~bs~aSe rrqiiiat&unmmjoapmpidoquepaim&sgorrlecudoi,&anidYnKnwpMminimizarh ~ r c p m uooadzl d ~al homhr duruiu ia d o n

riraducción Airtores]

Peregrine Falcon ( F h pmknus) recovery now returned to pre-DDT leveis (Kiff 1988, Newhas been documcnted in several rqions of the ton 1979. Ratcliffe 1993). The ban on DDT use world (FFe 1988, Kiff 1988, e1993, En- in many c o u n m a (Ratcliffe 1993) and the suc(Fyfe 1988, d m n et al. 1995). Nesting temtoria, deserted ccss of Peregrine recovery produring the decline of the sp& are now being Ratdi&t 1993) has conmbutcd to thc Peqpine's reoccupicd by brecding pairs, Rcproducaon has bcmod kom endangered status and to a redaign

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Figure 1. Rtcent records of n a u n g Peregrine Faicons o n h e c e n d wcst coast of Baja California. .Mexicr>.(Shadcri areas are Banks. 1969 records.)

of iu rnanagement saaup;ies (Walton and Thelander 1988). The histoncai and currmt stanu of the Mexican Peregrine Faicon population is not well known (Banks 1969. Fyfeet al. 1976). Populauons in the Baja Caiiiornia peninsula and the Gulf of C a i i f o ~ nia are known to have declined betwcen 196744 (Poner et d. 1988). By 1976. the Baja w a t coast population. once containing 38 breeding pain. was considered on the bnnk of extirpation (Fyfe et d. 1976). However. rccent reporo of newly occupied n a t i n g tcrritona in this arca (Daneman and Cuzmán &o 1992. Castellanos a al. 1994) mggest a informarion on current numbm. duuiburion. and praductivity of Peregrines. and dUcuss rheir con-

servation needs on the west central coact of thr Baja Caiifornia peninsula The study arca, a put of El Vizaino biosphere reserve, c o v m about 350 km aiong the west coast of Baja California. Mcxico (Fig. 1). T h c study arca includa: descn islands. a coasial fringe of m o d v a n d v b e a c h e a n d rwo big coutal I q m n s with extensive wetlanb ( M a r r y a n d Palacios 1994). Mort of the arca i i covered with halophytic vegctauon, 30 cm high. .Mountains are m v i c t e d io Benitos a n d Cxdros lslanb and %>meparu of h e El Vizcaíno r m e . We u& three data sourcm o n the breeding p o p u k [ion of Peregrine Falcons in the arca. Data from 198085 were obtained by F. Jaramillo d ~ i r i n gwildlife i n v e n m r i e io promote the creauon of thc El Vucaino Reserve and in 1994 on Cedros and Benitrn Islanb. Dara from Ojo d e Liebre and San Ignacio lagoonr were obrained by

A Castellanos E Salinas C ArpeUa and A Onega in 199S94. N a ~ sgw e y s of breeding Peregrine Falcons wem conducted by vMhing the plauaru canyom, hilis and b& on foot and kpecring aU povntial n a M g atm urLig binoculam. h a were u x d to explore the hgoonr and m rcacb the irlands. We aiso used mmt m o r b in the oological coUection of the Wcsurn Foundaaon of Vrrrcbratic Zoology (m) and personai pom k m 0th- individuai obacmrr We c o m p a d our dam with hose of BInjLI (1969).F'roducmiityof breeding pairs was atimavd by checlúng t h r e n a u in 1993 and five n a a in 1994.

We locared at least 10 n a ~ pain g of Peregrine Falcons in six locations in the survey area. including s m d islands in the open sca, isleu inside coastal lagoons and an inland mouneuious zone (Fig. 1). The maUmum number of pairs scen in a single ycar was si.p a h in 1994 when we observed pain on San Roque islan* Laguna Ojo de Liebre ( P i e dras Island and El Chaparrito navigaaon channel) and San Ignacio Lagoon (Pelicano and W e n a Islands) (Fig. 1. Table 1). k w not al1 the historical and potentiai nating sies were survrvyed, we considered thb to be a minimum atimate of the total number of brteding pairs in the arca The historicai popuiaaon estimate for the smdy arca was about 13 pairs (Banlcr 1969). Breeding pait.s were found on small clifñ. dimtly on the ground. in Osprey nesu and on anificial saucnues sudi as channel marken and ship wrecks. Ojo de Liebre (Scammon's) lagoon nest sies were n m (Castellanos et al. 1994). Lack of iniand n a n n g rccords írom the smdy arca led w to belicve that the diBF-naMg pain on Pácific North Vucaino (near Siena San José de Castro) were a h n m to the brc«üng popuiaaon. A nating record in the WFVZ reponed by B. ~ e i t h c k a n in 1981 documentcd a pair n a M g at San Ignacio Lagoon for the first time. Danand Guzmán Poo (1992) also found two pairs n a M g there in 1989. In addition to the 10 n a M g p a h . there were smral recmt single sightings and two probable nest site reporu írom Benitos and Cedros isiands (Fig. 1. Table 1). Ncamsc nesting site distanca va^ ied between 4.4 and 60 )un. Nesu were 4.4 )un apartin San Ignacio lagoon and 8 and 22 )un apart in Ojo de Liebre lagoon (Fig. 1) We foiiowed thc r e p r o d u c h succerr of thrcc pain during 1993 and five pairs durkig 1994. 1~ t c at d Ojo de Liebre and San Ignacio Lagoons. An amage of 3 egp. 1.8 natlingr, and 1.6 fledg-

lings were produced per n a t (Table 2). This pro. ductiviq appeared ro be within the range of producuviq for healthy populations (C;ide et. al. 1988, Ratciiffe 1993). The Peregrine Falcon is defined bv Murican law ar a vulnerable s p e a a (Diario Oficial 16 de Mayo de 1994). In spite of iu status. lack of nacional rc covery programs on rhreatened species has táiied to produce management plans in their &Murican range. The we of organochlorine pcsúades in the region u not weU documented but ir has apparentiy been reduced since the late 1970s. Studia conducted then and in the late 1980s in Baja California. the Culf of California and in nonhwestern Mexican waterfowl winuring areas show pesticide levek in cggs and bird -es are arnong the lowest in Nonh America (Spieer et al. 1977. ,Mora et aL 1987). This cvidence lea& LLS to belicve rhat current organochlorine pesticide w does not r e p r c sent a major thrcat for Peregrina in the region. We did. howcver. idenafy o t h a threaa to breeding Peregrines in the arca. N a u on the ground are accessible eo dogs and cau abandoned by f i h ermen-i,cthe islands. Coyotes (Canú labanc) umporanly invade' Piedras island in Ojo de Liebre lagoon datroying the nests of Peregrina. Osprcys and other birds. We found coyote nadcr at one failed Peregrine nest in 1994 and presumeti the coyote caused the nest Mure. AYian depredaaon by W a m Culls (h ouidenlalis) and Comrnon Ravens (Corvur m)is also a problem. Culls and ravens apparentiy cauxd the disappearance of three egp from a nest on a tower over the water in Ojo de Liebre lagoon. A thkd m d more serious threat . t ..nesripg Peregrines in the arca u írom humans when hhing. rourLm and other human acrivines caw inadcntal disturbanca at nars (Daneman and Cuzrnaxx P w 1992). The smdy arca is srill relarivcly inacccs sible and partiaiiy uninhabitcd. thus, habicat d o smcaon apparentiy is not yet a factor of concern. The coartal lagoons. islands and wetlands within the smdy arca suppon a magnificent avifauna which provida adequate numben and varicy of Peregrine p r y ( M a s s y and Palacios 1993). Nenheless. thc dmsity of breeding Peregrine F A cons in the arca seems to be rather l w for such an ideal locaaon. Most of the rtsidcnt p a h poned are coastai or "4 island Peregrina" (RatcWe 1993) nuting on d or mn o n the ground This is apparentiy k u s c of a shortage of suitable nanual nesting sites on the rnain-

Table 1. Hktorical and recent m o r & of nesting Peregrine Faicons in [he ccnual wrsr c o u t ot' Baja California. Recen t records are h m 1980-94.

Sui Benitos lrlands Waikcr. 1927 and 1950 Tyfer. 8 April 1930 Harrison. 1 April 1938 22 Yarch 1992

N a t with 2 q g s N a t with 2 eggs 1 seen

Banh (1969) 'IKFVZ. this srudv l+W. ihis srudv Tliis studv

Common. brccding Nest with 4 cggs I =en 1 xcn 1 pair. 2 sightings 1 female. 1 maie

Banh (1969) 11732. tliis studv This srudv Thu studv ThU s t u d ~ ThU smdy

Sedirist. 12 March 1917

Nest with 4 cggs

Lamb, Decemkr 1924 D.S.D.. 6 April 1930 Bancroft. 3 April 1932 SI Juiy 1985

6 pain rcsident Ncst with 3 cgp 2 n a t with cgp 1 bmding pair

WFW, this study Banks (1969) WCVZ. this studv WCVZ, this smdy Thh study

Cedros Island Kaeding, 1905 Carpenter. 2 April 1932 8. 31 ju1y and 18 Augur 1980 AprilIW1 2, 3 and 15 March 1992 22 March 1992

4nau

Ojo de Liebre Lagoon 26 Jan1982 June. October, N o w m k 1984 29 July 1985 21 Septemkr 1985 1993 ((uteUanoi et al. 1994)

1 ven 1 seen 2 femaie, and 2 males l m S breeding pair

Thu study Thu smdv This rriidr

Sui Roque h n d Huey. 20 April 1927 D.S.D.. 5 April 1930 Hanison. 6 April 1932 L Rorcs. 1994

N a t with 2 e ~ g ~ Nest with 3 q g ~ Ne,t with 4 q p 1 breeding pair

Banks í 1960) Nrn-2 -,vRrZ. 1Ili.u ituriv L. Rorcs pen. comm.

Aauncion Island Walker. 1938

1 pair

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San Ignacio Lagoon

Reithcrman. 11 April 1981 Septernbcr 1985 Daneman & Cuzmán Poo, 1992 March-June. 1994

Ncst. 2 young. 2 e g g ~ 1 pair. one s e r n 2 breeding pairs 2 breeding pair

WFVZ. thu study Thu snidy Daneman & Cuzmán Poo. 1992 Thu itudy

13 June, 1984 June 1984

1 brreding p d r 1 breeding p d r

4 Navember 1984 March and S e p v m k 1985

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PEREGWNE RECO~ZRY

,UCH 19Y7

Table 2. P e r w n e Faicon reproducuve success during 1993-1994 on the Scammon's and San Ignacio lagoons. 1993 ~CLH-

1994

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' ~ i c k e " [Ed.]. Per&ne Falcon ~ ~ u l a r i o n sUniv. . Wisconsin Preu. .Vadison. WI 6.S-A. -E. T.,J. ESDEWN. C THEUYDER.&VD C.V. WHITE. 1988. The role o í o ~ n o c h l o r i n epesucides in Peregrine populanon changa. P a g a 463-468 in T. G d e ,

SAN

SIXH-

IN .BAJACUFORVL~

J. Endemn. C Thelander and C. Whire [E&.]. Per-

MON'S YON'S ILVACIO crgrine Faicon populauons: their mmagement and reL\COON L\COON L C ~ N covery. The Peregrine Fund. B o k , ID U.SA

Occupied n a u checked Roductive nrsu T o d eggs laid Eggs failed to hatch Eggs disappeared Eggs broken .lvenge clutch sue Naclings Nacling disappear* Total young fledged Naclings/occupied n a t Fledglings/occupied n a t Fledglings/productiv n a t

3 3 10 1

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3 1 10

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3.3 9 1 8 S 2.6 2.6

3.3 3 1 2 1.0 0.6 2.0

3 1 4

1 4.0 3 3 1.5 1.5, 3.0

CASELLVOS,A. F. WNAS-Z~VU .UD .A. O K ~ u - R ~ 1994. Status and reproducrion of the Perqrine Faicon ara c o a r d lagoon in Baja Cdifomia Sur, .Uexico. J. Rnpfm Or. 38:110-1 12. DASLUV, C.D. .LYDJ. G t i z W POO. 1992. Nora on the birds of San l p a c i o lagoon. Baja Cdíiomia Sur. .Mexico. \tk&rn B i d 25: 11-1 9. DIARIOOFICIN OE La ~ E D E R \ C I ~ P ( . 1994. Tomo CDWCYIX. No. 10. 16 de Mayo d e 19%. Secretaría de Gobernación. ENDERSON. J.H.. W. HEINRICH,L Kim AVD C..M. W H BIO.

1995. Populations changes in Nonh hmerican P e m p i n a Paga 142-1 61 in T m s . 60th Nonh American wildlife and n a d resourca conference. Wildlife ' Robably avian and c o m e depredaoon. Management Instinite. Washington. DC U.SA Unknown causes. M, RW. 1988. The Canadian Peregrine Falcon recouery program -1967-1985. Paga 599410 in T. Cade. J. Endenon. C Thelander and C. iYhiu [E&.], Pereland c o a & inland and on s m d Ulan&, a factor that limiu cliff-nesting in ( R ~ ~ - grine Falcon popiilanons: their managemcnr and reC ~ C in ~ e . Peregrine Fund. Boisc ID U.SA clifie 19g3). do t a ~ eadvantage of 1976. The 1979 able artificial nesting sires when chey were avaiiable Rn. RW.. SA. TLWPLE.WD T.J. -E. hrncan PCTegrine Falcon sUTVYY Crin. Fd in the snidy arca (Castellanos et al. 1994) N& 90:228-273. Given hese circumstancespwe i m ~ l c m-, LF. 1988. Changa in b e s m m of h e Prrq+ne mentarion of a Peregrine Consewation P r w in in ~~d herica: paga 123-1 39 i n T. the El Vizcaino Reserve. focusing on the f ~ l l o w i n ~ Cade, J. Endrrson. C. Thelander 2nd C. Whitr [Eds.l. a) regular survevs of hktoricd and new nrstihg terP e r e n e Falcon popularions: their management and recovery. The P e r w n c Fund. Boisc. ID C.S.A. ritories to assess the current population statiis and . ~ S Y E B.W. Y , .LVD E. P.L\