Thamnophilidae - Antbirds Antbirds are in an insectivorous family that includes many forest understory species, but some are found higher up in the subcanopy while others are terrestrial. Most are well suited to living in tropical habitats, including forest interior and second growth, as well as various specialized microhabitats like gaps and vine tangles. The most unifying feature of the family is their bill shape which has a terminal hook and a pinched base. Many species are dimorphic in plumage with males being grayish to black with variably white wingbars, wing spots, tail spots, concealed intrascapular patch, or other black-and- white patterning. The females are often brownish, rufous-orange, or tawny, often similar in pattern to the male, except that blacks are replaced by brown colors contrasting with brighter orange or buffy barring. Although sexual dichromatism is common in the family, the obligate ant-followers either minimize this (i.e. Gymnopithys) or are not dichromatic (e.g. Pithys). The most common molt strategy of the family is the Complex Basic Strategy. The first preformative molt can be partial to complete and may be related to the amount of time self-sufficient young remain within their parent’s territory. Species that follow their parents for some time after fledging often retain a female-like plumage through a partial first preformative molt such that young birds can be distinguished by their distinct molt limits. However, juveniles of species that probably disperse away from their parents at an early age appear to have formative plumages similar to that of the adult plumage or have a complete first prebasic molt. Delayed plumage maturation is at best minimal for some species at the BDFFP; the definitive plumage is achieved no later than upon completion of the 2nd prebasic molt, but in some species the definitive plumage is achieved upon completion of the 1st preformative molt. The skull completes in adults, probably at about 6 months of age, but more study is needed to pin down the exact timing. Both sexes share in incubation and often develop brood patches, but are usually more developed in females. In most species, the timing of breeding often corresponds with the dry season, but there are exceptions as well as some asynchrony in these populations with some individuals breeding at any time of the year, sometimes when less than 1 year of age (before definitive plumage is achieved). Molt often occurs after the breeding season, but is again highly asynchronous in these populations. Molt-breeding overlap is frequent. # species at BDFFP: 28 # species netted: 22 # primaries: 10 # secondaries: 9 # rectrices: 12 Cymbilaimus lineatus lineatus – Fasciated Antshrike Band size: F-G # Individuals Captured: 23 Similar Species: Fine black and white barring throughout body of ♂ is unique at PDBFF. ♀ most like ♀ of Frederickena viridis, but smaller with barred black and white back and wings. Measurements: 100 Wing ♂ 70.5-74.0 (72.4 ± 1.3; n13) ♀ 70.0-78.0 (73.3 ± 2.8; n10) 80 Tail ♂ 65.0-72.0 (68.8 ± 2.3; n12) 60 ♀ 66.0-79.0 (71.4 ± 4.1; n8) Mass ♂ 29.0-39.0 (35.3 ± 2.7; n13) 40 ♀ 30.0-40.0 (33.5 ± 2.9; n9) Bill ♂ 13.9 (n1) 20 ♀ 14.5 (n1) 0 Tarsus ♂ 29.5 (n1) % birdswith molt (closed circles) or bp(open circles) Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec ♀ 28.9 (n1) Molt, n =110331244123 Skull: Probably completes (n2), but no other Bp, n =000001030010 information available. Brood Patch: Observed in 3 ♀♀ in Aug and probably possible in ♂♂ as they share in incubation, which may occur at least between Jul and Nov (HBW). Molt-breeding overlap is 0.0% (n3). Molt: Little information available, but probably Complex Basic Strategy. Ryder and Wolfe (2009) state that PF1 is incomplete or eccentric, but we suspect that PF1 of C. l. intermedius can complete based on 28 specimens at LSU and may also complete in C. l. lineatus. PBs are complete and the PA is apparently absent. Based on 1-4 captures per month (none in Mar) at the BDFFP, there appears to be two periods when complete wing molt occurs: Apr to May and Sep to Nov. No birds were observed in molt between Dec and Feb (n5) and from Jun to Aug (n7). Individual birds may have very flexible schedules and may molt during both periods of molt. Three birds have been recaptured; all were in PB (i.e. wing feathers were molting) upon initial capture (2 in May and 1 in Dec) and all had evidence of tail molt upon recapture 6-7 months later. Whether this is evidence of a new molt is unclear; it is possible that the replacement of lost tail feathers was misclassified as molt or that the annual timing of molt is highly variable. Age/Sex: BASIC I: ♀≠♂ (?) ♀ - May have black barring on rusty-brown crown as in C. l. intermedius. Iris may be brown. ♂ - Perhaps like Basic I ♀, but with narrower markings on pp and ss. Iris may be brown. FORMATIVE I: ♀≠♂ ♀ - This may be the definitive plumage, but is unknown. Some birds may have molt limits among the remiges in which case the B2 would be the definitive plumage. Iris may be dull red or orange. ♂ - This may be the definitive plumage. Look for molt limits among the remiges in some individuals. According to HBW, “subadult” ♂♂ have broader white barring on crown and body, but it is unclear if this refers to the B1or F1. Cymbilaimus lineatus lineatus – Fasciated Antshrike BASIC II: ♀≠♂ ♀ - The definitive plumage. The underparts are buffy- white and faintly barred black. The upperparts are boldly barred black and buff- white. The crown is solid rusty-brown. Iris is bright red. ♂ - The definitive plumage. Has relatively narrow white barring on crown and body with narrow white barring on the outer webbing of remiges (B). Iris is bright red (C). Frederickena viridis (no subspecies) – Black-throated Antshrike Band size: H # Individuals Captured: 110 Similar Species: ♂ most like Percnostola rufifrons, but larger and lacks white-tipped wing covs. ♀ most like Cymbilaimus lineatus, but larger with solid rusty-brown wings and upperparts. Measurements: 100 Wing ♂ 88.0-98.0 (92.0 ± 2.3; n44) ♀ 86.0-98.0 (91.9 ± 2.7; n44) 80 Tail ♂ 67.0-86.0 (75.8 ± 3.7; n42) 60 ♀ 65.0-84.0 (75.8 ± 3.9; n38) Mass ♂ 58.7-77.5 (67.1 ± 4.1; n46) 40 ♀ 61.0-77.0 (67.4 ± 3.9; n51) Bill ♂ 15.3-16.0 (15.7 ± 0.4; n3) 20 ♀ 15.9-16.6 (16.3 ± 0.5; n2) % bird with molt (solid lines) or bp (dotted lines) (dotted bp or lines) (solid molt with bird % 0 Tarsus ♂ 38.6-41.6 (39.7 ± 1.7; n3) Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec ♀ 38.8-39.0 (38.9 ± 0.1; n2) Molt, n =2 7 111315211616128 238 Skull: Completes (n9), possibly during the Bp, n =000022612161 PF1, but more study is needed. Brood Patch: Only ♀♀ have been observed with BPs (n3), between Jun and Nov, but ♂♂ also probably develop BPs. Molt-breeding overlap is 0.0% (n3). Molt: Complex Basic Strategy: PF1 complete, PBs complete. Molt peaks (>70%) in Dec and Jan and is least frequent (<15%) in Aug and Sep. Age/Sex: BASIC I: ♀=♂ Like the definitive ♀, but the iris is dull brown and the maxilla and especially mandible has extensive yellow. The remiges are unmarked brown and the chest is barred black gray and white and is less boldly patterned than in definitive ♀♀. 1st PREFORMATIVE MOLT: ♀≠♂ ♀ - Can be similar to definitive ♀♀, but the dull brown iris and yellowish bill are retained into the PF1 and are useful characteristics to separate PF1 ♀♀ from definitive ♀♀ when early in molt. The iris color changes to red and the bill turns black by the completion of PF1 and should not be used to age birds in later stages of molt. ♂ - Mixed gray and brown. Iris and bill features as in PF1 ♀♀. Frederickena viridis (no subspecies) – Black-throated Antshrike FORMATIVE I: ♀≠♂ ♀ - The definitive plumage. Has finely barred black and white underparts, tail, and face. The crown, back, and wings are solid rusty-brown. Iris is reddish orange to red. Bill is all black. ♂ - The definitive plumage. Unmarked charcoal gray underparts, back, and wing with faintly barred gray tail. Iris is red. Bill is all black. Note: There is variation in the strength of barring on the rects that may be age/sex related, but more study is needed. Thamnophilus murinus murinus – Mouse-colored Antshrike Band size: E # Individuals Captured: 228 Similar Species: ♂ from other medium-sized, all-gray antbirds (e.g. Thamnomanes caesius) by grayish iris, brownish wings, and faint white tips to wing covs. ♀ from other brown antbirds by contrastingly brighter rufous crown, grayish iris, and overall lack of pattern. Measurements: 80 Wing ♂ 54.0-65.0 (60.3 ± 1.8; n101) ♀ 54.0-64.0 (59.7 ± 1.9; n77) Tail ♂ 47.0-61.0 (52.2 ± 2.6; n98) 60 ♀ 49.0-59.0 (52.9 ± 2.1; n71) Mass ♂ 15.0-22.0 (17.5 ± 1.1; n117) 40 ♀ 15.0-22.0 (18.0 ± 1.6; n86) Bill ♂ 10.2-12.9 (11.5 ± 0.8; n11) 20 ♀ 10.7-12.1 (11.4 ± 0.5; n10) Tarsus ♂ 20.0-23.2 (21.3 ± 0.9; n11) (solidlines) birdswith molt or bp (dotted % 0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec ♀ 20.9-23.0 (22.0 ± 0.7; n11) Molt, n = 13 8 15 19 18 21 20 38 26 41 32 16 Skull: Completes (n24) during F1.