Mourning Warbler

Table

Mourning Warbler – Accepted
1. 03 Oct 1968	HY	Pt. Loma SD	1985-013	11	SDNHM 36933
2. 16 Sep 1973		Bolinas MRN	1986-179	11
3. 17–18 Sep 1974		Southeast Farallon I. SF	1986-178	11
4. 25 Sep 1974		Southeast Farallon I. SF	1986-176	11	ph.
5. 25 Sep 1974	HY	Southeast Farallon I. SF	1978-082	11	ph., Roberson (1980)
6. 25 Sep 1974		Southeast Farallon I. SF	1984-037	11	ph.
7. 26 Sep 1974		Southeast Farallon I. SF	1986-177	11
8. 29 May 1976		Furnace Creek Ranch INY	1976-037	3
9. 04 Jun 1977		Mesquite Spring INY	1977-117	4
10. 03 Jun 1978		Southeast Farallon I. SF	1987-116	14	ph.
11. 02 Sep 1979		Pt. Mugu VEN	1980-026	7
12. 14 Sep 1979	HY	Southeast Farallon I. SF	1988-023	14
13. 23 Sep 1979		Southeast Farallon I. SF	1980-198	7	ph.
14. 27–30 Sep 1979	HY	Pt. Reyes MRN	1979-061	7,9	ph., Roberson (1980)
15. 10 Nov 1979	HY	Baker SBE	1987-355	14	SBCM 30529
16. 30 Jun–01 Jul 1980		Southeast Farallon I. SF	1980-199	7
17. 09–10 Sep 1980	HY	Southeast Farallon I. SF	1988-024	14
18. 20–23 Sep 1980		Carpinteria SBA	1980-214	7
19. 10 Oct 1980	HY	Southeast Farallon I. SF	1987-209	14	ph., Pyle & Henderson (1990)
20. 10 Oct 1980	HY	Southeast Farallon I. SF	1987-117	14
21. 29–31 Aug 1981		Carmel R. mouth MTY	1981-054	7	ph.
22. 06–07 Sep 1981		Carpinteria SBA	1981-071	7
23. 07–12 Sep 1981		Pt. Reyes MRN	1981-049	7
24. 13–14 Sep 1981	HY	Southeast Farallon I. SF	1988-025	14
25. 14 Sep 1981	HY	Southeast Farallon I. SF	1988-026	14
26. 17 Sep 1981		Refugio State Beach SBA	1982-012	7
27. 26 Dec 1981–28 Jan 1982		Wilmington LA	1982-018	7
28. 20–22 Jun 1982		Pt. Reyes MRN	1982-086	8
29. 24 Sep–04 Oct 1982		Carpinteria SBA	1982-105	8
30. 08 Oct 1982	HY	Pt. Loma SD	1982-111	9
31. 22 May 1983		Tule Lake NWR SIS	1983-043	8
32. 28 May 1983		Oasis MNO	1983-041	8	ph., Morlan (1985)
33. 18 Sep 1983	HY	Pt. Mugu VEN	1983-130	9
34. 20 Sep 1983	HY	Pt. Loma SD	1983-123	9
35. 17 Sep 1984	HY	Carpinteria SBA	1988-096	14
36. 20 Sep 1984		Southeast Farallon I. SF	1987-119	11	ph.
37. 05 Oct 1984		Big Sur R. mouth MTY	1984-271	10
38. 25 May 1985		Mesquite Spring INY	1985-107	11
39. 04–06 Sep 1985		Southeast Farallon I. SF	1985-182	11	ph.
40. 21 Sep 1985		Tijuana R. valley SD	1986-066	11
41. 26 Sep 1985		Goleta SBA	1985-173	11
42. 16 May 1986		California City KER	1986-331	12
43. 03 Sep 1986		Southeast Farallon I. SF	1987-066	12	ph.
44. 07 Sep 1986	HY	Montaña de Oro State Park SLO	1986-366	14
45. 10 Sep 1986		Southeast Farallon I. SF	1987-067	12	ph.
46-47. 12 Sep 1986	2	Southeast Farallon I. SF	1987-064/1987-065	12	ph., Langham (1991)
48. 20 Oct 1986		Southeast Farallon I. SF	1987-006	12
49. 04 Nov 1986		Carmel R. mouth MTY	1986-436	12
50. 07 Jun 1987		Southeast Farallon I. SF	1987-148	12	ph.
51. 15 Jun 1987		Southeast Farallon I. SF	1987-210	13	ph.
52. 27–28 Aug 1987	HY	Southeast Farallon I. SF	1987-248	13	ph.
53-54. 13 Sep 1987	HY, HY	Southeast Farallon I. SF	1988-013/1988-014	13	ph.
55. 13 Oct 1987	HY	Southeast Farallon I. SF	1988-015	13	ph.
56. 14–15 Jun 1988	SY	Southeast Farallon I. SF	1988-153	13	ph.
57. 30 Aug 1988	AHY	Southeast Farallon I. SF	1988-166	13	ph., Pyle & Henderson (1990)
58. 05–20 Sep 1988		Huntington Beach ORA	1988-255	15
59. 08–11 Sep 1988		Southeast Farallon I. SF	1988-299	13	ph., Pyle & Henderson (1990)
60. 15–16 Sep 1988	HY	Goleta SBA	1988-277	13
61. 08 Oct 1988	HY	Carmel R. mouth MTY	1988-182	13
62. 06–09 Sep 1989	AHY	Southeast Farallon I. SF	1989-176	15	ph.
63. 06–08 Sep 1989	HY	Southeast Farallon I. SF	1989-177	15	ph.
64. 08 Sep 1989	HY	Southeast Farallon I. SF	1989-178	15
65. 09 Sep 1989	HY	Southeast Farallon I. SF	1989-179	15
66. 20 Sep 1989	HY	Southeast Farallon I. SF	1989-180	15	ph.
67. 23–27 Sep 1989		Montaña de Oro State Park SLO	1990-019	15	ph.
68. 20 May 1990		Mojave KER	1990-077	15
69. 05–08 Sep 1990		Mad R. mouth HUM	1991-064	16
70. 13 Sep 1990		Gaviota SBA	1990-176	16
71. 23 Sep 1990		Carpinteria SBA	1990-178	16
72. 28 Sep 1990		Carmel R. mouth MTY	1990-142	16
73. 30 Sep 1990		Southeast Farallon I. SF	1991-011	16	ph.
74. 07–11 Jun 1991		Southeast Farallon I. SF	1991-081	16	ph.
75. 07 Sep 1991	HY	Southeast Farallon I. SF	1991-162	17
76. 10 Sep 1991	HY	Palomarin MRN	1992-082	17	ph.
77. 13 Sep 1991		Goleta SBA	1991-228	17
78. 14–17 Sep 1991		Pt. Reyes MRN	1991-120	17
79. 15–16 Sep 1991	HY	Southeast Farallon I. SF	1991-163	17	ph.
80. 20–21 Sep 1991	HY	Southeast Farallon I. SF	1991-164	17
81. 06 Oct 1991	HY	Southeast Farallon I. SF	1992-006	17	ph.
82. 22 May 1992		Mojave KER	1992-155	18
83. 30–31 Aug 1992	HY	Southeast Farallon I. SF	1992-252	18	ph.
84. 20 Sep 1992	HY	Pt. Reyes MRN	1992-255	18
85. 05 Oct 1992	HY	Furnace Creek Ranch INY	1992-270	18
86. 15 Sep 1993		Stinson Beach MRN	1998-009	22
87. 30 Sep 1993		Bolinas MRN	1998-010	22
88. 01 Oct 1993		Southeast Farallon I. SF	1993-210	19	ph.
89. 02–03 Oct 1993		Rodeo Lagoon MRN	1993-180	19
90. 04–05 Oct 1993		Southeast Farallon I. SF	1993-211	19	ph.
91. 06–07 Oct 1993		Southeast Farallon I. SF	1993-212	19	ph.
92. 31 May 1994		Big Sur R. mouth MTY	1994-106	20	ph., Roberson (2002:411)
93. 29 Aug 1994	HY	Southeast Farallon I. SF	1995-045	20	ph.
94. 13 Sep 1994	HY	Southeast Farallon I. SF	1994-199	20	ph., Howell & Pyle (1997), possible hybrid
95. 15–18 Sep 1994		Galileo Hill KER	1994-154	23	Fig. 287, ph., AB 49:102
96. 17 Sep 1994	HY	Westend SBE	1994-134	20
97. 25 Sep 1994	AHY	Southeast Farallon I. SF	1994-200	20
98. 31 Dec 1994–25 Feb 1995	AHY	Newport Beach ORA	1995-011	20
99. 26 Sep 1996	AHY	Southeast Farallon I. SF	1997-036	23	ph.
100. 01 Oct 1996		Moss Beach SM	1996-136	22
101. 11–13 Oct 1996	HY	Carmel R. mouth MTY	1996-137	22
102. 14 Sep 1997	HY	Oxnard VEN	1998-065	23	ph.
103. 20 Sep 1997	HY	Morro Bay State Park SLO	1998-038	24
104. 24–28 Sep 1997	HY	Los Angeles LA	1997-157	23	ph., Rottenborn & Morlan (2000)
105. 17 Jun 1998		Harkins Slough SCZ	1999-025	27
106. 12–13 Sep 1998	HY	San Nicolas I. VEN	1998-136	24
107. 15–16 Sep 1998	HY	Southeast Farallon I. SF	1999-014	24	ph.
108. 04 Sep 1999	AHY	Southeast Farallon I. SF	2000-021	25	ph.
109. 11–12 Sep 1999	HY	Pt. Pinos MTY	1999-184	25
110. 12 Sep 1999	HY	Tunitas Creek SM	2000-033	25
111. 15 Sep 1999	HY	Southeast Farallon I. SF	2000-016	25	ph.
112. 25 Sep 1999		California City KER	1999-165	27	ph., video, Garrett & Wilson (2003),
					possible hybrid
113. 17–18 Jun 2000		San Nicolas I. VEN	2002-141	28
114. 04–05 Oct 2001		Southeast Farallon I. SF	2002-019	27	ph.
115. 05 Oct 2001		Arcata HUM	2001-168	28
116. 07 Oct 2001		Southeast Farallon I. SF	2002-018	27	ph.
117. 26 May 2002		Furnace Creek Ranch INY	2002-108	28
118. 22–24 Aug 2002		vic. Bishop INY	2006-207
119. 31 Aug 2002	HY	Southeast Farallon I. SF	2003-010	28	ph.
120. 11 Sep 2002		Mojave KER	2002-157	28
121. 21–25 Sep 2002	AHY	Pt. Loma SD	2002-160	28
122. 26 Sep 2002	HY	Southeast Farallon I. SF	2003-009	28	ph.
123. 26 May 2003		Ridgecrest KER	2003-062	29
124. 19 Sep 2003	HY	Pt. Loma SD	2003-122	29	sketch in San Miguel & McGrath (2005)
125. 02 Oct 2003	HY	California City KER	2003-131	29
Mourning Warbler – Not accepted, identification not established
12–14 Jun 1968		Deep Springs INY	1984-101	14	MacGillivray’s Warbler, banded 12 Jun, collected 14 Jun, MVZ 159292
31 May 1974		Santa Barbara I. SBA	1980-012	24	also reviewed as Connecticut Warbler
24 May 1975		Deep Springs INY	1975-025	3
19 Sep 1975		Pt. Reyes MRN	1986-351	14
28 May 1977		Deep Springs INY	1977-057	4
13–14 Sep 1981		Southeast Farallon I. SF	1988-025	16	possible hybrid, Richardson et al. (2003)
08 Sep 1984		Southeast Farallon I. SF	1987-118	13	ph., possible hybrid, Pyle & Henderson (1990:228; 1991), Richardson et al. (2003)
27 Sep 1986		vic. Oxnard VEN	1987-042	13
25 May 1987		Furnace Creek Ranch INY	1987-179	12
13 Sep 1989		Gaviota SBA	1989-155	16
20 Sep 1989		Montaña de Oro State Park SLO	1990-018	17
03 Oct 1990		Oceano SLO	1991-043	17
08 Oct 1990		Huntington Beach ORA	1991-044	17
15 Sep 1991		Pt. Loma SD	1991-208	17
09 Oct 1992		Galileo Hill KER	1993-022	18	ph.
24 Sep 1994		Galileo Hill KER	1994-136	21
31 Aug 1996		Ferndale HUM	1997-048	24
24 Sep 1996		Hansen Dam LA	1997-026	24
14 Sep 1997		Galileo Hill KER	1997-132	23
13 Jun 1998		Southeast Farallon I. SF	1999-015	27
19 Sep 1998		Big Sur R. mouth MTY	1999-066	24
16 Oct 1998		Mt. Diablo CC	1999-064	24
16 Oct 1998		Iron Mtn. Pumping Plant SBE	1998-224	25
18 Sep 1999		Pt. Reyes MRN	1999-153	25
28 May 2000		White Slough Wildlife Area SJ	2000-093	26	possible hybrid
27 Sep 2000		Southeast Farallon I. SF	2001-028	28	ph.
23 Dec 2001		Palos Verdes Peninsula LA	2002-056	28
18 Aug 2003		Mono Lake County Park MNO	2003-125	29
13 Oct 2003		San Clemente I. LA	2004-012	31	ph.
Mourning Warbler – Not submitted
11 Jun 1971		Donner State Park NEV			AB 25:904
23 Sep 1982		Goleta SBA		14	Lehman (1994)
21 Sep 1984		Pt. Reyes MRN		14	AB 39:100
02 Oct 1985		Pt. Loma SD		14	AB 40:160
19 Sep 1990		Pt. Loma SD			AB 45:153
01 Sep 1995		S. Fork Kern R. Preserve KER			FN 50:118, “banded”
27–29 Oct 1995		Long Beach LA			FN 50:118
22 Sep 1996		Big Sur R. mouth MTY			Roberson (2002)
26 May 1999		Butterbredt Spring KER			NAB 53:331
fall 1999		Southeast Farallon I. SF			NAB 54:102, see table entries 108, 111
15 Sep 1999		Big Sur R. mouth MTY			Roberson (2002)
11 Sep 2000		Big Sur R. mouth MTY			Roberson (2002)
11 Sep 2000		Southeast Farallon I. SF			NAB 55:100
13 Sep 2001		Little R. mouth HUM			Harris (2006)
22 Aug 2002		vic. Bishop INY			NAB 57:118

Figures

Figure 287. Birders frequently, and understandably, have trouble distinguishing Mourning and MacGillivray’s Warblers, particularly when confronted with birds that seem to show intermediate characters. Partially on the basis of the described calls, and after reviewing other photographs that showed the bird’s yellowish throat, the Committee concluded that this individual—photographed on 15 September 1994 at Galileo Hill in Kern County—was a Mourning (1994-154; Matthew T. Heindel).

Figure 420. Distribution of 125 Mourning Warblers accepted through 2003. Southeast Farallon Island accounts for nearly half the state’s total. Otherwise, records are concentrated along the southern and central coast and at the oases of eastern Kern County and Inyo County. Only three records come from the state’s northern third.

Figure 421. The Mourning Warbler’s pattern of vagrancy to California is comparable to the Connecticut’s (see Figure 419). Mournings have been recorded more frequently before mid September, and more frequently in spring, with a peak in late May (no Connecticut yet appeared before June). Most exceptional are the state’s two winter records.

Mourning Warbler

MOURNING WARBLER Oporornis philadelphia (Wilson, 1810)

Accepted: 125 (81%)	Treated in Appendix H: no
Not accepted: 29	CBRC review: all records
Not submitted/reviewed: 15	Large color image: see Figures

This warbler’s northern breeding limit extends from extreme southeastern Yukon and northeastern British Columbia east to Newfoundland. The southern limit reaches from northeastern North Dakota east to northwestern Massachusetts and locally south through the Appalachian Mts. to West Virginia and Virginia. Migrants avoid, for the most part, crossing the Gulf of Mexico, particularly in spring, and instead follow the Atlantic slope of Middle America to and from wintering grounds in southern Central America and northern South America; there is one winter record from Oaxaca. Transients occur casually to rarely in the Southeast and casually in the West Indies and in the West, where most are encountered along the Pacific coast from southern British Columbia south through Baja California Sur. Accidental records exist from south-central Alaska and Greenland.

California’s first Mourning Warbler was a first-fall female collected on 3 October 1968 at Pt. Loma, San Diego County (McCaskie 1970g). This followed a 12 June 1968 specimen from Deep Springs, Inyo County, that was reported as a Mourning but proved to be a MacGillivray’s (Roberson 1993). As with the similarly secretive and closely related Connecticut Warbler, roughly half of the state’s records (55 of 125) come from Southeast Farallon Island (Figure 420). Our understanding of this species’ status in California derives in large part from the substantial body of well-documented records from this ornithological mecca. Most reports of Mourning Warblers from Southeast Farallon involve birds measured and photographed in the hand, leading to a 93% acceptance rate (55 of 59). Elsewhere in the state, only 75% of records (70 of 94) have garnered Committee endorsement.

The Mourning Warbler’s seasonal pattern of occurrence mirrors that of the Connecticut Warbler, but its schedule is less restricted (Figure 421). Five out of every six records (103 of 125) involve fall vagrants, with bracketing dates of 22 August and 10 November; September accounts for about three-fourths of them (73 of 103). The 20 spring records fall between 16 May and 1 July, peaking in late May, and no bird is known to have oversummered. California’s two winter records are unique north of southern Mexico: 26 December 1981–28 January 1982 at Harbor Regional Park, Los Angeles County, and 31 December 1994–25 February 1995 in Newport Beach, Orange County.

Mourning Warbler field identification is complicated by considerable variation among age/sex classes (Pyle 1997b) and by apparent, but presumably rare, hybridization with MacGillivray’s Warbler, the Mourning’s sibling species. Few hybrids have been reported (Cox 1973, Patti and Myers 1976, Hall 1979, NAB 58:426), and their existence has even been contested, with odd birds being referred to as variant Mourning Warblers (Pitocchelli 1990, 1992, 1993). Nonetheless, specimens of reported hybrid origin exist (e.g., SDNHM 39095; see Cox 1973), and birds with intermediate characters have been captured, measured, and photographed on Southeast Farallon Island (see Pyle and Henderson 1990) and at Deep Springs, Inyo County, 20 May 2000 (T. and J. Heindel unpubl. data). A few other records, some of them accepted by the CBRC, involve birds with intermediate features (e.g., relatively bold eye arcs but a yellow throat). See the preceding account for useful references addressing the identification of Oporornis warblers.