Yellow-headed Blackbird (Xanthocephalus xanthocephalus)

Photo by Ryan Brady Yellow-headed Blackbird by Ryan BradyYellow-headed Blackbird distribution map

Status/Protection

Population Information

The Federal BBS information can be obtained at http://www.mbr-pwrc.usgs.gov/bbs/bbs.html by clicking on Trend Estimates and selecting the species in question. All estimates are for time period (1966-2005).

Life History

Habitat Selection

The Yellow-headed Blackbird breeds in deep-water marshes, sloughs, forested wetlands, and along lake edges (Twedt and Crawford 1995). In Wisconsin they are most common in open, lowland marshes (Volkert 2006). They are colonial nesters with colony sizes in Wisconsin varying from several to >100 pairs (Robbins 1991, Volkert 2006). Nests are attached to cattails, bulrushes, or reeds above deeper water, ranging from 16-76 cm in Wisconsin. Competitive interactions with Red-winged Blackbirds typically result in Red-wingeds being forced into marsh edge habitats containing shallower water (Minock and Watson 1983). Yellow-headed Blackbirds forage within wetlands and surrounding open agricultural and upland areas (Twedt and Crawford 1995).

Habitat Availability

Prior to Euro-American settlement, wetlands occupied an estimated four million hectares of the total fourteen million hectares of Wisconsin’s land area. Today, 53% (2.1 million hectares) of these wetland habitats remain. However, agricultural drainage and urban development threaten remaining wetland ecosystems and local populations of wetland-associated birds. Human activities that alter hydrology and introduce invasive plant species also threaten wetland habitats (WDNR 2003). Strict wetland use regulations and incentive programs designed to restore or enhance wetlands have helped to curb habitat loss and protect existing wetlands (WDNR 1995).

Population Concerns

Historical evidence in Wisconsin indicates dynamic population trends throughout the twentieth century (Ellarson 1950). The Yellow-headed Blackbird is considered a fairly common summer resident in south and central Wisconsin, and an uncommon summer resident in the north (Robbins 1991). Its localized distribution makes it a difficult species to survey by conventional methods. Breeding Bird Survey (BBS) data suggest a non-significant population increase range-wide and non-significant decline in Wisconsin (Sauer et al. 2005). However, BBS methodology may not provide adequate coverage at colony sites. Wisconsin Breeding Bird Atlas observers visited colony sites from 1995-2000 and confirmed breeding activity in approximately 6% of the surveyed quads. Atlas observers estimated that 40 blocks had 2-10 breeding pairs, 26 blocks had 11-100 pairs, and 5 blocks had >100 pairs (Volkert 2006).

The drainage of marshes has led to the disappearance of colonies in the state (Volkert 2006), but also has resulted in geographic isolation of the Wisconsin population. Wisconsin is at the eastern edge of the Yellow-headed Blackbird’s breeding range. Thus, without connectivity of wetlands, the migration corridor is compromised and recruitment to the population is likely reduced (Ward 2005). Furthermore, the colonial nature of Yellow-headed Blackbirds makes them vulnerable to local extinctions. Events such as lethal control for crop depredation may have devastating consequences to local breeding populations if applied at colony or roost sites (Twedt and Crawford 1995).

Recommended Management

Management efforts should focus on preserving all existing emergent deep-water wetlands, but particularly those harboring breeding colonies. At colony sites, managers should consider maintaining water depth at 30 cm or more (Minock and Watson 1983) and promoting the growth of tall, robust emergent vegetation such as cattail and hard-stem bulrush. The continuation of wetland management, protection, and restoration efforts such as the Wetlands Reserve Program, Partners for Fish and Wildlife, and North American Wetland Conservation Act will benefit this species. Wetland restoration efforts should target areas in Wisconsin and surrounding states that will increase connectivity and re-establish a migratory corridor (Ward 2005).

Research Needs

More information is needed on habitat use, range, and behavior during winter (Twedt and Crawford 1995). In Wisconsin, targeted surveys in suitable wetland habitats would help to elucidate its status in the state. The absence of colonies in apparently suitable habitat needs further study (Minock and Watson 1983). At known Wisconsin colony sites, studies documenting recruitment rate, reproductive success, and adult survival would help to identify limiting factors.

Information Sources

References

Contact Information

Kreitinger, K., Y. Steele and A. Paulios, editors. 2013.
The Wisconsin All-bird Conservation Plan, Version 2.0. Wisconsin Bird Conservation Initiative.
Wisconsin Department of Natural Resources. Madison, WI.

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