Fr: Géospize des mangroves
All: Mangrovedarwinfink
Esp: Pinzón de Darwin Manglero
Ita: Fringuello delle mangrovie
Nd: Mangrovevink
Sd: Mangrovefink

Photographer:

Roger Ahlman
Pbase Galleries Peru and Ecuador

Text by Nicole Bouglouan

Sources:

HANDBOOK OF THE BIRDS OF THE WORLD Vol 16 by Josep del Hoyo- Andrew Elliot-David Christie – Lynx Edicions – ISBN: 9788496553781

Avibase (Lepage Denis)

BirdLife International (BirdLife International)

ARKive (Christopher Parsons)

HBW Alive

Wikipedia, the free encyclopaedia

Talking Naturally

The Royal Society – Biological Sciences

 

Home page

Page Order Passeriformes

Summary cards

 

Mangrove Finch
Camarhynchus heliobates

Passeriformes Order – Thraupidae Family

Darwin’s Finches - Generalities

INTRODUCTION:
The Mangrove Finch is classified as critically Endangered like the Medium Tree-Finch. It is endemic to the Galapagos Islands and included in the Darwin’s Finches group of which it is the rarest species.  
This species has very restricted range on Isabela Island. Its population was estimated 40-43 pairs in 2010, located in two mangroves on Isabela. However, these numbers appear more stable today, and may even be increasing now.  

DESCRIPTION OF THE BIRD:
Biometrics:
Length: 14 cm
Weight: 18 g

The adult male has grey-brown upperparts with indistinct streaks or unstreaked plumage. Wings and tail are brown. We can see two narrow, diffuse, pale wingbars.
The underparts are white with grey streaks on throat, breast and flanks.
On the head, the face is grey-brown with pale area around the eye.
The bill appears fairly long with arched culmen, but the gonys is almost straight. It is black when breeding, and with paler lower mandible outside the breeding period. The eyes are dark. Legs and feet are blackish-grey.
The older birds may acquire a black hood.

The female resembles male in plumage, but she has dull orange bill with darker culmen and tip according to the season.
The juvenile is similar to the female.

Female

RANGE:  
The Mangrove Finch occurs in the W part of Isabela Island, in W Galapagos Islands.

HABITAT:  
The Mangrove Finch, as indicated by its name, frequents dense mangroves swamps with tall trees, separated from the sea. The ground is covered with thick leaf litter and dead wood. Actually, the separation of the mangroves from the sea prevents the washing-out of the leaf litter forming the suitable soil where it can find its favourite preys.
But in spite of the separation from the sea by large beaches and bare lava fields, the soil is saturated with sea water. On each side, some parts of the ground are covered with thick thorn scrub Scutia pauciflora.
These mangroves are regularly flooded at high tide. However, the leaf litter, plant debris and dead wood cannot be removed and form the forest floor so appreciated by the Mangrove Finch. Such sites are very rare on arid islands.

CALLS AND SONGS: SOUNDS BY XENO-CANTO
The Mangrove Finch gives high-pitched call « zeeeee » and a buzzy « zzzzzz-tuu ».
The song is a cheerful and happy “chi’ priip chi’ prriip chi’ prrip”, or more interrogative “ch-wee? che-wee? che-wee?”

BEHAVIOUR IN THE WILD:
The Mangrove Finch feeds primarily on arthropods such as insects and their larvae, mainly Coleopterans, and spiders. It also takes some plant matter and fruits when available.
It forages in dead wood and leaf litter. It uses its strong bill to prise off the bark from dead wood, in order to extract invertebrates.

But like the Woodpecker Finch, it may use tools such as cactus spines or twigs held in the bill, to reach the preys hidden in hollows and cavities in the wood.

The pairs may have long-term pair-bonds during several breeding seasons. They are monogamous. They breed during the hot, wet season, during the rainy season.
They nest in tall trees in mangroves which are flooded at high tide, although being separated from the sea.

The Mangrove Finch is resident within its restricted range and only performs short flights.

REPRODUCTION OF THIS SPECIES:  
The breeding season occurs from December-January into May, during the rainy season.
The male builds a spherical nest with an entrance at side towards the top. It is typically made with dry grasses, moss and lichens. It is usually placed in the outer branches in the lower canopy of Avicennia germinans (black mangrove) or Laguncularia racemosa (white mangrove). The nest is generally in tall tree, in patches of mangroves flooded at high tide.

The female lays 4 whitish eggs with darker spots. She incubates alone during 12 days. The young birds fledge about 10-15 days after hatching.
The nests are often parasitized by the fly Philornis downsi, a nest parasite.  

PROTECTION / THREATS / STATUS:
The Mangrove Finch is rare and very local. It has small populations established in two mangroves on Isabela. The species is now extinct on Fernandina.
It is threatened by introduced predators, and mainly by the Black rat (Rattus rattus) causing nesting failures. The nest parasite Philornis downsi is also a significant threat, like the avian pox.
In addition, this species is living in rare habitat. It is also threatened by habitat loss due to natural events.
The Mangrove Finch is classified as Critically Endangered, but it is protected within the Galapagos National Park, and conservation measures are on their way.