Chapala Birders Newsletter, May 2, 2021 | | 159 Species Seen in April | | The complete list appears at the end of this newsletter. Highlights this month included:
- A Bald Eagle was photographed by Paul Hart at the El Volantin dam. Four weeks prior, one was seen in Nayarit State 200km away. We think it was probably the same bird. They are exceptionally rare this far south.
- Carlo Cuevas saw Lesser Nighthawk and Blue-black Grassquit at La Cañada.
- Jules Evens reported Vaux's Swift and Dusky Flycatcher in San Antonio Tlayacapan.
Global Big Day - Saturday May 8
Once again this is a day when really keen birders, often in a team, get up before dawn and go to the best bird sports until after dark, in order to record the largest list of species that they can. Everyone is invited to take part by going birding on May 8 and then recording their list on eBird. Last year more than 50,000 birders in 175 countries submitted bird lists for Global Big Day. | | Featured Bird: Ladder-backed Woodpecker | | A male Ladder-backed Woodpecker at its nest-hole in a fence post at the Pumping Station (Photo by Ajijic birder Paul Hart). | | - The Ladder-backed Woodpecker is a year-round resident of our area, being found throughout Mexico and in the southern states of the US. It is non-migratory. It is the second most common woodpecker at Lake Chapala.
- It lives mainly in dry habitats like deserts and thorn forest, but is also seen in river woods and pine-oak woods.
- The female is similar to the male but is slightly smaller and lacks the red patch on the hind crown.
- The nest cavity is excavated in a tree, pole or cactus. The female lays 2 to 7 eggs which are incubated by both sexes for 13 days. The parents also share in the feeding of the nestlings for two weeks.
- Their food is predominantly insects and grubs found in the crevices of trees, but also fruit when available.
| | The Challenge
Forty percent of the world's bird species are migratory. Long-distance migration is a dangerous endeavor subject to many hazards. It is estimated that a third of the birds that set out on long-distance migrations die on the way. Most birds migrate at night.
How far do birds migrate?
- Local Migration: Some travel locally, like the Sparkling-tailed Hummingbird which visits Lake Chapala for six weeks in May to perform one nesting cycle. We think they travel only 100km.
- Altitude Migration: Some fly to lower altitudes in the winter, like the Blue-black Grassquit which is here all summer nesting at 1,500m, but in most years it moves to the coastal hills of Jalisco 200km away to winter below 1,000m where it is warmer.
- Long-distance migration: Many fly great distances like the Wilson's Warbler which winters in Mexico and Central America and breeds in California, Canada and Alaska. It travels four to five thousand kilometers each way.
- The Super Fliers: A few species fly across the oceans, like the Bar-tailed Godwit which leaves Alaska in September. heading south across the Pacific Ocean to fly almost non-stop for seven days to arrive in New Zealand 11,000km away. In March, it flies back but stops in China to build up fat reserves before continuing on to Alaska making the return journey a total of 17,000km.
Knowing when to go
The primary method is by sensing the relative length of the days. This is processed in the visual analysis area of the brain. When the day-length is right, hormones are produced to initiate the migration cycle. The timing is intended to allow the birds to arrive on the nesting grounds when there will be plentiful food for the baby chicks. Actual departure occurs when weather conditions are right for flying at night.
How do they navigate?
Birds have more 'senses' than we do.
- Visual. Birds not only see more colors than us, but they are sensitive to the polarization of sunlight which helps in direction finding. When flying in sunshine, birds are also able to compensate for the time of day to determine correct direction. At night, birds are able to recognize the constellations to help navigate. Landmarks along the way are stored as visual information in the hippocampus area of the brain. This is important since so many species exhibit 'nesting site fidelity' returning every year to where they were born.
- Magnetic. Birds are sensitive to magnetic field strength, as well as to the inclination and the polarity of the magnetic field. It is not clear yet whether this is part of the olfactory system or is in the eyes or both. Analysis of brain activity at night when birds are orienting without light, a part of the brain known as cluster 'N' in the 'Visual Wulst' is particularly active. It is speculated that bird brains deliver some kind of "image" of the magnetic field just as the brain delivers an image of the visual field of view based on the nerve signals received from the eyes.
Next month: Where do birds get the energy to fly so far? | | We are proposing to continue with our reduced-size birdwalks for which you must reserve a place by email ( chapalabirders@yahoo.com) ahead of time. Masks will be worn and social distancing will be required. There will be no indoor activity, meaning no group breakfast at the end of the walk. Maximum attendance will be ten people, or in the case of a car trip, a maximum of three cars with a maximum of three people per car.. Please reserve a space by email at least 48 hours ahead of each birdwalk or bird trip.
On Thursday May 6, we will meet at 8.15 at Donas Donuts, departing immediately for Villa Corona on Lake Atotonilco (60 minutes drive). We expect to see various shore birds such as White-faced Ibis and Roseate Spoonbill. Bring your own mid-morning refreshments. There will be a break for snacking at 11.00 am. We will be back in Ajijic by about 1.30 pm. You must reserve - email John at least 2 days ahead of time, indicating if you can bring a vehicle or if you would like to be a passenger.
On Monday May 17, we will meet at 8.15 at the Old Train Station in Chapala, leaving immediately to bird the "Chapala Lakeshore East" including the pumping station. Expect to see a good variety of shore birds in a variety of habitats. We will bird until 10.30am.You must reserve - email John at least 2 days ahead of time indicating if you can bring a vehicle or if you would like to be a passenger. The train station is on the Lakeshore Road just east of Cristiania Park in Chapala.
On Wednesday May 26, we will meet at 8.15 at Donas Donuts leaving immediately for the Sierra de Tapalpa (90 minutes away). We will bird from 9.30 till 12.30. We expect to see higher altitude birds such as Acorn Woodpecker and Slate-throated Redstart and if we are lucky Trans-volcanic Jay. Bring your own refreshments for the morning and sandwiches for lunch. We will be back about 5.00 pm. You must reserve - email John at least 2 days ahead of time indicating if you can bring a vehicle or if you would like to be a passenger. | | On April 6, we went to El Bajio on the west side of Ajijic with a party of four birders. We managed to sight Violet-crowned and Broad-billed Hummingbirds in the tall Jacaranda trees, Blue Mockingbird, Black-backed and Black-vented Oriole, Stripe-headed Sparrow and Western Tanager, out of total of 44 species.
On April 15, we traveled with a party of three to Lake Cajititlan where we saw 42 species including Northern Harrier, Black-headed and Blue Grosbeak, Mourning Dove, Fulvous Whistling Duck, Common Raven, White-tailed Kite and Rufous-backed Robin.
On April 26, there were six keen birders at the Allen Lloyd Trail where we identified 33 species, including Rusty-crowned Ground Sparrow, Red-tailed Hawk, Russet-crowned Motmot, Northern Beardless Tyrannulet, Golden-fronted and Ladder-backed Woodpecker and Happy Wren. | | Here are the 159 species sighted around Lake Chapala in April:
Ani, groove-billed Avocet, American (Ca,Ra) Blackbird, red-winged (Ps,Ra) Blackbird, yellow-headed (Ca,Ra) Bunting, indigo Bunting, lazuli Bunting, painted (Sa) Bunting, varied Bushtit Caracara, crested Chat, yellow-breasted Coot, American Cormorant, neotropic Cowbird, bronzed Cowbird, brown-headed Cuckoo, squirrel Dove, common ground (Ps,Ra) Dove, Eurasian collared Dove, Inca Dove, mourning (Ca) Dove, white-tipped Dove, white-winged Dowitcher, long-billed Duck, black-bellied whistling (Xt) Duck, fulvous whistling (Ca) Duck, Mexican Duck, ruddy (Ca,Ra) Eagle, bald (Ra) Egret, cattle Egret, great Egret, snowy Elaenia, greenish Euphonia, elegant Finch, house Flycatcher, ash-throated Flycatcher, cordilleran (Sa) Flycatcher, dusky Sa) Flycatcher, dusky-capped Flycatcher, gray (Sa) Flycatcher, gray silky Flycatcher, least (Sa) Flycatcher, social Flycatcher, sulphur-bellied Flycatcher, vermilion Gallinule, common Goldfinch, lesser Grackle, great-tailed Grassquit, blue-black (Xt) Grebe, least (Ra) Grebe, pied-billed (Xt) Grosbeak, black-headed Grosbeak, blue Gull, laughing Gull, ring-billed Harrier, northern (Ca) Hawk, Cooper's Hawk, red-tailed Hawk, sharp-shinned Hawk, white-tailed (Ra) Hawk, zone-tailed (Av) Heron, black-crowned night Heron, great blue Heron, green (Ps) Heron, little blue (Ps) Heron, tri-colored (Ps) Hummingbird, berylline Hummingbird, broad-billed Hummingbird, violet-crowned Hummingbird, white-eared (Jo) Ibis, white-faced Jacana, northern Kestrel, American Killdeer Kingbird, Cassin's Kingbird, thick-billed (Av) Kingbird, tropical Kiskadee, great Kite, white-tailed (Ca) Meadowlark, eastern Ra) Mockingbird, blue Mockingbird, northern Motmot, russet-crowned Nighthawk, lesser (Xt) Nightjar, buff-collared Oriole, black-backed Oriole, black-vented Oriole, Bullock's Oriole, orchard Oriole, streak-backed Owl, ferruginous pygmy (Sa,Av) Owl, great horned Parakeet, monk Pelican, American white Pewee, greater Pewee, western wood Pigeon, rock Pipit, American (Ch) Raven, common Redstart, American Roadrunner, greater (Ra) Robin, rufous-backed Sandpiper, least Sandpiper, spotted Sandpiper, western Seedeater, cinnamon-rumped Shoveler, northern (Ca,Ra) Solitaire, brown-backed Sparrow, chipping Sparrow, clay-colored Sparrow, house Sparrow, lark (Ca,Ra) Sparrow, Lincoln's Sparrow, rusty-crowned ground Sparrow, savannah Sparrow, stripe-headed Spoonbill, roseate (Ra) Stilt, black-necked Stork, wood (Ra) Swallow, barn Swallow, cliff (Ch,Jo) Swallow, northern rough-winged Swallow, tree (Ca) Swift, Vaux's (Sa) Tanager, western Teal, blue-winged Teal, cinnamon Teal, green-winged Tern, Caspian Tern, Forster's Thrasher, curve-billed Thrush, orange-billed nightingale (Sa) Towhee, canyon Tyrannulet, northern beardless Vireo, black capped (Sa) Vireo, Cassin's Vireo, golden (At,Sa) Vireo, plumbeous (Sa) Vireo, warbling (Sa) Vulture, black Vulture, turkey Warbler, black and white Warbler, black-throated gray Warbler, MacGillivray's (Sa) Warbler, Nashville Warbler, orange-crowned Warbler, rufous-capped Warbler, Virginia's (Sa) Warbler, Wilson's (Av) Warbler, yellow (Ch) Warbler, yellow-rumped Waxwing, cedar (Ps) Woodpecker, golden-fronted Woodpecker, ladder-backed Wren, Bewick's Wren, canyon Wren, happy (Sa) Wren, spotted Yellowthroat, common (Ra) Yellowthroat, gray-crowned (Ps) | | Sighting Location codes: Ac - Ajijic: La Cristina / El Bajio At - Trails above Ajijic Av - Ajijic village Ca - Lake Cajititlan & marsh Ch - Chapala Ct - Caracol Trail / Int'l School Dm - Dike: Jamay to Malteraña Dp - Dike: Maltaraña to La Palma Hv - Hidden Valley oak forest Ja - Jamay La - La Cañada-Hidden Valley Jo - Jocotepec Ld - Lerma & Duero rivers Oc - Ocotlan Pe - Petatan area Ps - Pumping Station/Santa Cruz Pt - San Pedro Tesistan area Pz - San Pedro Itzican area Ra - Rosa Amarilla loop Rc - Santa Rosa/Carnero dam Rp - Riberas del Pilar & canyon Sa - San Antonio/Allen Lloyd Trail Sc - San Juan Cosala Sn - San Nicholas/Golf Club Tz - Tizapan canyon Te - San Juan Tecomatlan / Mezcala Tr - Las Trojes / oak forest Tu - Tuxcueca / San Luis Soyatlan Xt - Ixtlahuacan / Las Campanillas | | | Lake Chapala Birders is an informal group of bird observers led by John and Rosemary Keeling.
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