Some 30 years ago, when I first began traveling to South Africa to hunt birds, it was Clayton’s father, Trevor, whose voice reverberated across these wetlands that line the course of the Blood ...

“You need to be able to keep the blood meal fluid and prevent the host from kicking you out,” Dr. Ben Mans, who studies hematophages at South Africa’s Agricultural Research Council, told Salon.

It's not just Africa facing declining populations of birds. In a 2019 study, scientists said that the U.S. and Canada have lost 29% of their bird populations — amounting to nearly 3 billion birds.

PARIS (AFP) — The flamboyantly plumed secretary bird and the serpent-catching snake eagle are among dozens of Africa's large birds of prey facing a human-driven "extinction crisis" researchers said on ...

Researchers at Lund University in Sweden have discovered that bird blood produces more heat in winter, when it is colder, than in autumn. The study is published in The FASEB Journal.

For each bird tested, Juarez fills out a tally sheet, documenting its species, age, weight, sex (if it can be determined), whether the bird was previously banded, and amount of blood drawn.

A version of this article appears in print on Jan. 9, 2024, Section A, Page 7 of the New York edition with the headline: Africa’s Birds of Prey Are in Stark Decline, New Research Finds.